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Sample records for actinide isotope content

  1. Actinide isotopic analysis systems

    This manual provides instructions and procedures for using the Lawrence Livermore National Laboratory's two-detector actinide isotope analysis system to measure plutonium samples with other possible actinides (including uranium, americium, and neptunium) by gamma-ray spectrometry. The computer program that controls the system and analyzes the gamma-ray spectral data is driven by a menu of one-, two-, or three-letter options chosen by the operator. Provided in this manual are descriptions of these options and their functions, plus detailed instructions (operator dialog) for choosing among the options. Also provided are general instructions for calibrating the actinide isotropic analysis system and for monitoring its performance. The inventory measurement of a sample's total plutonium and other actinides content is determined by two nondestructive measurements. One is a calorimetry measurement of the sample's heat or power output, and the other is a gamma-ray spectrometry measurement of its relative isotopic abundances. The isotopic measurements needed to interpret the observed calorimetric power measurement are the relative abundances of various plutonium and uranium isotopes and americium-241. The actinide analysis system carries out these measurements. 8 figs

  2. Production of actinide isotopes in simulated PWR fuel and their influence on inherent neutron emission

    This report describes calculations that examine the sensitivity of actinide isotopes to various reactor parameters. The impact of actinide isotope build-up, depletion, and decay on the neutron source rate in a spent-fuel assembly is determined, and correlations between neutron source rates and spent-fuel characteristics such as exposure, fissile content, and plutonium content are established. The application of calculations for evaluating experimental results is discussed

  3. Radiochemical studies of neutron deficient actinide isotopes

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, 242Bk, was produced with a cross-section of approximately 10 μb in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, αxn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,αxn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z1 + Z2 = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,αxn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of 228Pu, 230Pu, 232Cm, or 238Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes

  4. Radiochemical studies of neutron deficient actinide isotopes

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, /sup 242/Bk, was produced with a cross-section of approximately 10 ..mu..b in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, ..cap alpha..xn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,..cap alpha..xn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z/sub 1/ + Z/sub 2/ = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,..cap alpha..xn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of /sup 228/Pu, /sup 230/Pu, /sup 232/Cm, or /sup 238/Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes.

  5. Characterization of Tank 48H Samples for Alpha Activity and Actinide Isotopics

    This document reports the total alpha activity and actinide isotopic results for samples taken from Tank 48H prior to the addition of sodium tetraphenylborate and MST in Batch number-sign 1 of the ITP process. This information used to determine the quantity of MST for Batch number-sign 1 of the ITP process and the total actinide content in the tank for dose calculations

  6. Actinide isotopic analysis system for Los Alamos Plutonium-Handling Facility

    This paper reports that inventory measurement of a sample's total plutonium and other actinides content by non-destructive assay is an important component of safeguarding special nuclear material. Gamma-ray spectromety measurements of relative isotopic abundances, coupled with a calorimetry measurement, can determine sample SNM content for inventory measurement. The Actinide Isotopic Analysis System (AIAS) is a newly developed two-detector gamma-ray spectrometry-based system that will determine isotopic ratios of Pu and U, Np, and Am abundances relative to plutonium for the Nuclear Material Storage Facility at Los Alamos National Laboratory. spectral analysis is performed using Multiple Group analysis (MGA) program or a customized version of the Group Analysis (GRPANL) computer program. The system can measure samples containing reactor grade plutonium, weapons grade plutonium, and plutonium enriched in either 238Pu or 242Pu (>50%). Software that controls the system is driven by a user-friendly menu of options

  7. Preparation of isotopes and sources of actinide elements

    As the C.E.A. possesses no isotopic separation facility, the productions of isotopes of actinide elements are performed: a) by neutron irradiation and chemical treatment of special targets, b) by milking decay products from stocks of aged actinide elements, c) by chemical treatment of alpha active wastes. These productions concern the following isotopes: 233U, 238Pu, 242Pu, 243Cm, 242Cm, 244Cm (a); 228Th, 229Th, 234U, 237U, 239Np, 240Pu, 241Am, 248Cm (b); 237Np, 241Am (c). These isotopes are produced to satisfy French and international needs and are sent to users in various forms: solutions, metals, oxides, fluorides, or in different sources forms. The preparation of the sources represents an important field of activities divided into two parts: 1/Industrial sources: production of large series of different sources, 2/ Scientific sources: production of sources suitable for a specific scientific problem. A large overview of these activities is given

  8. LSDS Development for Isotopic Fissile Content Assay

    Concerning the sustainable energy supply and green house effect, nuclear energy became the most feasible option to meet the energy demand in Korea. However, the production of the spent nuclear fuel is the inevitable situation. Since the first nuclear power plant started to produce the electricity in Korea, the accumulated amount of spent fuels exceeded 10k tomes recently. The accumulation of the spent fuels is the big issue in the society. Therefore, as an option which strengthens the nuclear proliferation resistance and reduces the amount of spent fuels, sodium fast reactor (SFR) program linked with pyro-processing is under development to re-use the PWR spent fuel and produce the energy. In the process, the produced metallic material involves uranium and TRU (transuranic; neptunium, plutonium, and americium). The uranium-TRU is used to fabricate SFR fuel. The burning the recycled fuel in the reactor is to solve the current spent fuel storage problem and to minimize the actinides accumulation having long half-life. Generally, the spent fuel from PWR has unburned ∼1 % U235, produced ∼0.5 % plutonium from decay chain, ∼3 % fission products, ∼ 0.1 % minor actinides (MA) and uranium remainder. About 1.5 % fissile materials still exist in the spent fuel. Therefore, spent fuel is not only waste but energy resource. The direct and isotopic fissile content assay is the crucial technology for the spent fuel reuse. Additionally, the fissile content analysis will contribute to the optimum storage design and safe spent fuel management. Several nondestructive technologies have been developed for the spent fuel assay; gamma ray measurement, passive and active neutron measurements. Spent fuel emits intense gamma rays and neutrons by (a, n) and spontaneous fission. This intense background has the limitation on the direct analysis of fissile materials. Recently, to analyze the individual fissile content, leadslowing down spectrometer (LSDS) has been being developed in Korea

  9. Minor Actinide Transmutation Performance in Fast Reactor Metal Fuel. Isotope Ratio Change in Actinide Elements upon Low-Burnup Irradiation

    Metal fuel alloys containing 5 wt% or less minor actinide (MA) and rare earth (RE) were irradiated in the fast reactor Phénix. After nondestructive postirradiation tests, a chemical analysis of the alloys irradiated for 120 effective full power days was carried out by the inductively coupled plasma - mass spectrometry (ICP-MS) technique. From the analysis results, it was determined that the discharged burnups of U-19Pu-10Zr, U-19Pu-10Zr-2MA-2RE, and U-19Pu-10Zr-5MA were 2.17, 2.48, and 2.36 at.%, respectively. Actinide isotope ratio analyses before and after the irradiation experiment revealed that Pu, Am, and Cm nuclides added to U-Pu-Zr alloy and irradiated up to 2.0 - 2.5 at.% burnups in a fast reactor are transmuted properly as predicted by ORIGEN2 calculations. (author)

  10. Microcalorimeter Q-spectroscopy for rapid isotopic analysis of trace actinide samples

    We are developing superconducting transition-edge sensor (TES) microcalorimeters that are optimized for rapid isotopic analysis of trace actinide samples by Q-spectroscopy. By designing mechanically robust TESs and simplified detector assembly methods, we have developed a detector for Q-spectroscopy of actinides that can be assembled in minutes. We have characterized the effects of each simplification and present the results. Finally, we show results of isotopic analysis of plutonium samples with Q-spectroscopy detectors and compare the results to mass spectrometry

  11. Microcalorimeter Q-spectroscopy for rapid isotopic analysis of trace actinide samples

    Croce, M. P.; Bond, E. M.; Hoover, A. S.; Kunde, G. J.; Mocko, V.; Rabin, M. W.; Weisse-Bernstein, N. R.; Wolfsberg, L. E.; Bennett, D. A.; Hays-Wehle, J.; Schmidt, D. R.; Ullom, J. N.

    2015-06-01

    We are developing superconducting transition-edge sensor (TES) microcalorimeters that are optimized for rapid isotopic analysis of trace actinide samples by Q-spectroscopy. By designing mechanically robust TESs and simplified detector assembly methods, we have developed a detector for Q-spectroscopy of actinides that can be assembled in minutes. We have characterized the effects of each simplification and present the results. Finally, we show results of isotopic analysis of plutonium samples with Q-spectroscopy detectors and compare the results to mass spectrometry.

  12. An easy method for the determination of Ra isotopes and actinide alpha emitters from the same water sample

    Radium isotopes and actinide α emitters are easily determined from the same water sample. The Ra fraction is obtained by coprecipitation with Ba, while a Fe coprecipitation is used for the actinides. Both fractions are measured with a gas-flow proportional counter. Additionally the isotopic Ra composition is obtained by measuring at two or three different times the α activity from the Ra-fraction. The method is applied to rain water and drinking water samples. (author)

  13. The contrasting fission potential-energy structure of actinides and mercury isotopes

    Ichikawa, Takatoshi; Möller, Peter; Sierk, Arnold J

    2012-01-01

    Fission-fragment mass distributions are asymmetric in fission of typical actinide nuclei for nucleon number $A$ in the range $228 \\lnsim A \\lnsim 258$ and proton number $Z$ in the range $90\\lnsim Z \\lnsim 100$. For somewhat lighter systems it has been observed that fission mass distributions are usually symmetric. However, a recent experiment showed that fission of $^{180}$Hg following electron capture on $^{180}$Tl is asymmetric. An earlier experiment has shown fission of $^{198}$Hg and nearby nuclei is symmetric, but with hints of asymmetric yield distributions up to about 10 MeV above the saddle-point energy. We calculate potential-energy surfaces for a typical actinide nucleus and for 12 even isotopes in the range $^{178}$Hg--$^{200}$Hg, demonstrating the radical differences between actinide and mercury potential surfaces. We discuss these differences and how the changing potential-energy structure along the mercury isotope chain affects the observed (a)symmetry of the fission fragments. We show that the ...

  14. Actinides ultra traces detection and isotopic ratio measurements by mass spectrometry

    We present the mass spectrometry techniques used in the frame of the environmental monitoring of the centres of CEA, and non proliferation programmes, for the detection of ultra-traces of actinides (U and Pu), and for measurement of the corresponding isotopic ratios. They are plasma source (ICP-MS), thermo-ionization (TIMS), and secondary ions (SINS) mass spectrometry techniques. As the analyzed samples contain only tiny amounts of nuclear materials, from the femto-gram (10-15 g) to the pico-gram (10-12 g) range, these instruments must present excellent performances in terms of sensitivity and precision on isotopic ratio measurements. We describe the methodological and instrumental developments carried out on the spectrometers to obtain instrumental detection limits below the femto-gram. (authors)

  15. Actinide isotopes compositions and neutrons emission rate calculations for irradiated research reactors fuel

    the availability of burn-up data is an essential first step in any systematic approach to the enhancement of safety, economics and performance of research reactors. A computer program has been designed to solve the system of equations describing the depletion, decay and production of uranium, plutonium and transplutonium nuclides. monte Carlo code was used to calculate the effective one group microscopic cross sections averaged over ETRR-1 fuel cell. the compositions of actinide isotopes, burn-up and neutrons emission rate have been calculated as a function of irradiation time and cooling time. results indicate that the amount of plutonium produced and neutrons emission rate are strongly dependent on the fuel burn-up

  16. Theoretical studies of nuclear shapes for some lanthanide and actinide isotopes

    In the framework of geometric collective model (GCM) quantum phase transition between spherical and deformed shapes of doubly even nuclei are investigated. The model is formulated, it contains two kinetic energy terms and a potential given as a six term polynomial in two deformation parameters. The validity of the model is examined for the case of lanthanide chains Nd / Sm / Gd / Dy with neutron number N = 84 - 100 and actinide chains Th / U with neutron number N = 134 - 148. The parameters of the model were obtained by performing a computer simulated search program in order to obtain a minimum root mean square deviations between the calculated and the experimental excitation energies. Calculated potential energy surfaces (PES 's) describing all deformation effects of each nucleus are extracted. Our systematic studies on lanthanide and actinide chains have revealed a shape transition from spherical vibrator to axially deformed rotor when moving from the lighter to heavier isotopes.It is shown that the proposed model describes the collective structure effectively and illustratively, exhibiting the systematic nuclear shape changes. Collective properties are illustrated by the PES. The abnormal behavior of the two - neutron separation energies of our lanthanide nuclei as a function of neutron number around neutron number 90 is calculated. Nonlinear behavior is observed which indicate that shape phase transition is occurred in this region. The calculated reduced B(E2) transition probabilities of the low states of the ground state band in the nuclei 150Nd / 152Sm / 154Gd / 156Dy are analyzed and compared to the prediction of vibrational U(5) and rotational SU(3) limits of interacting boson model calculations.

  17. Ultra-low level (pg/L) actinide determinations and superior isotope ratio precisions by quadrupole ICP-MS

    A very high sensitivity, quadrupole-based inductively coupled plasma mass spectrometer (ICP-MS) has been developed and employed to measure very low concentrations (pg/L) of various actinides in solution. The detection capabilities of the instrument are shown using a variety of sample introduction methods, including simple direct sample nebulization, higher efficiency sample nebulization, and column preconcentration. This allowed three sigma detection limits in the range from 33 to 0.07 pg/L to be achieved, using short integration times, for a number of actinides. In addition, the improved sensitivity allowed isotope ratio measurements to be undertaken with good precision, (0.05 to 0.2%) at low concentrations (0.5 to 5 microg/L), without requiring long acquisition times. The results of isotope ratio measurements on silver, lead, and NIST natural lead standard SRM 981 will be reported

  18. Hydride interference on the determination of minor actinide isotopes by inductively coupled plasma mass spectrometry

    Hydrogen adducts of the major naturally occurring actinide isotopes 232Th and 238U were studied using an inductively coupled plasma mass spectrometer. The hydride:atomic ion ratios for both elements varied as a function of the parameters that were studied, i.e., nebulizer flow rate, solution uptake rate and desolvation conditions. When the instrument sensitivity for U and Th was optimized, 232ThH+:232Th+ was found to be (3.9±0.2) x 10-5 with pneumatic nebulization and (2.10±0.07) x 10-5 with ultrasonic nebulization. Under the same conditions, 238UH+:238U+ was found to be (3.2±0.2) x 10-5 and (1.8±0.1) x 10-5 using pneumatic and ultrasonic nebulization, respectively. Conditions that reduced hydrogen number density and/or increased plasma temperature decreased the hydride:atomic ion ratio. Such conditions are best if 233U and 239Pu are to be determined in the presence of 232Th and 238U. (Author)

  19. The contrasting fission potential-energy structure of actinides and mercury isotopes

    Ichikawa, Takatoshi; Iwamoto, Akira; Möller, Peter; Sierk, Arnold J.

    2012-01-01

    Fission-fragment mass distributions are asymmetric in fission of typical actinide nuclei for nucleon number $A$ in the range $228 \\lnsim A \\lnsim 258$ and proton number $Z$ in the range $90\\lnsim Z \\lnsim 100$. For somewhat lighter systems it has been observed that fission mass distributions are usually symmetric. However, a recent experiment showed that fission of $^{180}$Hg following electron capture on $^{180}$Tl is asymmetric. We calculate potential-energy surfaces for a typical actinide ...

  20. Actinide content and associated neutron emission of WWER-440 spent fuel - calculation and validation for safeguards purposes

    A major task of international nuclear material safeguards consists in the experimental determination of the characteristics of spent nuclear fuel. In this respect, passive neutron techniques take a prominent place. The paper describes both the actinide content and the passive neutron emission of spent WWER-440 fuel for a number of operational conditions. For validation purposes the results have been compared with those independently gained by other authors for the same type of fuel. The calculations are the basis for a true to fact interpretation of the primary measurement signal, i.e. for the inference from recorded neutron radiation regarding the properties of the spent nuclear fuel. (author)

  1. Climatic changes and isotopic content along the River Nile valley

    Full text: The stable isotope composition of rain and snow has considerable variation with climatology, with geography and with time at a given location. This variation primarily results from the lower vapour pressure of water molecules which contain heavy isotopes of deuterium and oxygen-18 compared to molecules consisting of only the lightest. Because of vapour pressure differences, heavier isotopes tend to be enriched in liquid phase relative to vapour phase. Subsequent precipitation formed from the depleted vapour will be progressively 'lighter' in stable isotope composition. Surface waters became enriched in deuterium and oxygen-18 relative to their initial isotopic composition as losses by evaporation occur. According to the IAEA precipitation sampling at Entebbe, which represent the source region of white Nile, with isotopic composition range (-33 to +4 per mille in δD and -5.7 to -1.1 in δ18O). The isotopic composition of precipitation station at Addis Ababa which is the main source of Blue Nile ranges from -8.4 to +7 per mille in δD and from -0.7 to -2.27 per mille in δ18O. Assuming the Central Africa run-off contribution to white Nile downstream of the Sudan represents 20% of natural discharge to Egypt, and the balance 80% is derived from Ethiopia (Blue Nile), we obtain a composite stable isotope composition of δD=-1 per mille and δ18O=-1.8 per mille, as an order of magnitude estimate on the probable long term stable isotope composition of the River Nile reaching upper Egypt under natural condition (before High Dam construction). Stable isotopes were used to estimate the evaporation from Naser Lake at the High Aswan Dam. According to isotopic content, the lake can be divided into two sectors; the first sector with pronounced vertical isotope gradients, and the second with subdued isotope gradients. Isotope content in surface waters varies with time and environmental effects (humidity, wind velocity,temperature, etc.). In order to detect this effect

  2. Diets of introduced predators using stable isotopes and stomach contents

    Meckstroth, A.M.; Miles, A.K.; Chandra, S.

    2007-01-01

    In a study of predation on ground-nesting birds at South San Francisco Bay (South Bay), California, USA, we analyzed stomach contents and stable isotopes of carbon and nitrogen to identify commonly consumed prey. We obtained the stomach contents from 206 nonnative red foxes (Vulpes vulpes regalis) collected in the South Bay area and Monterey County during 1995-2001 and from 68 feral cats (Felis silvestris) from the South Bay area during 2001-2002. We determined prey identity, biomass, and frequency, described seasonal diet trends, and derived an Index of Relative Importance. Avian species were the most frequent prey we found in the stomachs of red foxes from South Bay (61%), whereas small rodents were most frequent for red foxes from Monterey County (62%). Small rodents were the most frequent prey we found in feral cats (63%). Carbon and nitrogen isotopic signatures for foxes supported stomach content findings. However, isotope results indicated that cats received a majority of their energy from a source other than rodents and outside the natural system, which differed from the stomach content analysis. We demonstrated the utility of both stable isotope and stomach content analyses to establish a more complete understanding of predators' diets. This information aids natural resource managers in planning and evaluating future predator-removal programs and increases our understanding of the impacts of nonnative foxes and cats on native species.

  3. An Approach for Validating Actinide and Fission Product Burnup Credit Criticality Safety Analyses-Isotopic Composition Predictions

    The expanded use of burnup credit in the United States (U.S.) for storage and transport casks, particularly in the acceptance of credit for fission products, has been constrained by the availability of experimental fission product data to support code validation. The U.S. Nuclear Regulatory Commission (NRC) staff has noted that the rationale for restricting the Interim Staff Guidance on burnup credit for storage and transportation casks (ISG-8) to actinide-only is based largely on the lack of clear, definitive experiments that can be used to estimate the bias and uncertainty for computational analyses associated with using burnup credit. To address the issues of burnup credit criticality validation, the NRC initiated a project with the Oak Ridge National Laboratory to (1) develop and establish a technically sound validation approach for commercial spent nuclear fuel (SNF) criticality safety evaluations based on best-available data and methods and (2) apply the approach for representative SNF storage and transport configurations/conditions to demonstrate its usage and applicability, as well as to provide reference bias results. The purpose of this paper is to describe the isotopic composition (depletion) validation approach and resulting observations and recommendations. Validation of the criticality calculations is addressed in a companion paper at this conference. For isotopic composition validation, the approach is to determine burnup-dependent bias and uncertainty in the effective neutron multiplication factor (keff) due to bias and uncertainty in isotopic predictions, via comparisons of isotopic composition predictions (calculated) and measured isotopic compositions from destructive radiochemical assay utilizing as much assay data as is available, and a best-estimate Monte Carlo based method. This paper (1) provides a detailed description of the burnup credit isotopic validation approach and its technical bases, (2) describes the application of the approach for

  4. Stable isotope content of South African river water

    Variations of the isotopic ratios 18O/16O and D/H in natural waters reflect the variety of processes to which the water was subjected within the hydrological cycle. Time series of the 18O content of the major South African rivers over a few years have been obtained in order to characterise the main features of these variations in both time and space. Regionally the average '18O content of river water reflects that of the prevailing rains within the catchment. 18O variations with time are mainly correlated with river flow rates. Impoundments upstream and management of river flows reduce this correlation. Isotope variations along the course of a river show the effects of inflow from smaller streams and evaporation in the river or its impoundments. These observations indicate the use of isotopic methods to study the evaporation and mixing of river water and its interaction with the surrounding environment

  5. Generation of an actinide isotopes cross section set for fast reactor calculations using data from ENDL and ENDF/B-IV

    A Bondarenko format 25-group cross section set of actinide isotopes was generated for the fuel cycle evaluation and the incineration study in fast reactor systems. Evaluated Nuclear Data Library of Lawrence Livermore Laboratory (U.S.) was used as the source data. The actinide isotopes treated are the following 28: Th-232, U-233, U-234, U-235, U-236, U-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Pu-243, Am-241, Am-242, Am-243, Cm-242, Cm-243, Cm-245, Cm-246, Cm-247, Cm-248, Bk-249, Cf-249, Cf-250, Cf-251, Cf-252 and a pseudo-fission product. ENDF/B-IV was used for U-238. The set was then collapsed to one energy group using a large LMFBR core spectrum for the comparison with other one-group sets. (author)

  6. Dynamical approach to isotopic-distribution of fission fragments from actinide nuclei

    Ishizuka, Chikako; Chiba, Satoshi; Karpov, Alexander V.; Aritomo, Yoshihiro

    2016-06-01

    Measurements of the isotope distribution of fission fragments, often denoted as the primary fission yield (pre-neutron yield) or independent fission yield (post-neutron yield) are still challenging at low excitation energies, so that it is important to investigate it within a theory. Such quantities are vital for applications as well. In this study, fragment distributions from the fission of U isotopes at low excitation energies are studied using a dynamical model. The potential energy surface is derived from the two center shell model including the shell and pairing corrections. In order to calculate the charge distribution of fission fragments, we introduce a new parameter ηZ as the charge asymmetry, in addition to three parameters describing a nuclear shape, z as the distance between two centers of mass, δ as fragment deformation, and ηA as the mass asymmetry. Using this model, we calculated the isotopic distribution of 236U for the n-induced process 235U + n → 236U at low excitation energies. As a result, we found that the current model can well reproduce isotopic fission-fragment distribution which can be compared favorably with major libraries.

  7. Isotope ratio analysis of actinides, fission products, and geolocators by high-efficiency multi-collector thermal ionization mass spectrometry

    A ThermoFisher 'Triton' multi-collector thermal ionization mass spectrometer (MC-TIMS) was evaluated for trace and ultra-trace level isotoperatioanalysis of actinides (uranium, plutonium, and americium), fission products and geolocators (strontium, cesium, and neodymium). Total efficiencies (atoms loaded to ions detected) of up to 0.5-2% for U, Pu, and Am, and 1-30% for Sr, Cs, and Nd can be reported employing resin bead load techniques onto flat ribbon Re filaments or resin beads loaded into a millimeter-sized cavity drilled into a Re rod. This results in detection limits of 4 atoms to 105 atoms) for 239-242+244Pu, 233+236U, 241-243Am, 89,90Sr, and 134,135,137Cs, and (le) 1 pg for natural Nd isotopes (limited by the chemical processing blank) using a secondary electron multiplier (SEM) or multiple-ion counters (MICs). Relative standard deviations (RSD) as small as 0.1% and abundance sensitivities of 1 x 106 or better using a SEM are reported here. Precisions of RSD ∼ 0.01-0.001% using a multi-collector Faraday cup array can be achieved at sub-nanogram concentrations for strontium and neodymium and are suitable to gain crucial geolocation information. The analytical protocols reported herein are of particular value for nuclear forensic and nuclear safeguard applications.

  8. PC/FRAM: A code for the nondestructive measurement of the isotopic composition of actinides for safeguards applications

    Sampson, T.E.; Kelley, T.A.

    1996-12-01

    The Nuclear Safeguards Program at the Los Alamos National Laboratory has developed and fielded techniques for the gamma-ray spectrometry measurement of the isotopic composition of plutonium and other actinides for over 20 years, ever since Parker and Reilly first proposed a practical method for the measurement of the arbitrary sample. Their procedures, incorporating internal (to the measured gamma-ray spectrum) or {open_quotes}intrinsic{close_quotes} self-determination of the relative efficiency function of the sample-detector measurement system, are widely applied today. The PC/FRAM code is the most recent and most highly-developed Los Alamos code developed specifically for the nuclear safeguards applications of this technique. We will describe the measurement principles that allow accurate measurements to be taken on samples of arbitrary size, shape, and measurement geometry- and of arbitrary physical and chemical composition-through the use of known nuclear decay data (half-lives and branching intensities). Subsequently, we will describe the analysis methodology, which is driven by an easily edited parameter file that frees the user from dependence on a dedicated programmer for analyses of special cases. This methodology relies on internal gamma-ray peaks from the spectrum under analysis to self-calibrate the unknown spectrum for energy and peak shape (energy dependence of full width at half maximum (FWHM) and tailing parameters). The program uses these parameters to calculate response functions that are fit to the analysis peaks requested in the parameter file. The structure of the code and its Windows 3.1 user interface allows use with equal ease by the experienced spectroscopist or operator-level personnel in a working facility.

  9. Consistent Data Assimilation of Actinide Isotopes: 235U and 239Pu

    In this annual report we illustrate the methodology of the consistent data assimilation that allows to use the information coming from integral experiments for improving the basic nuclear parameters used in cross section evaluation. A series of integral experiments were analyzed using the EMPIRE evaluated files for 235U, 238U, and 239Pu. Inmost cases the results have shown quite large worse results with respect to the corresponding existing evaluations available for ENDF/B-VII. The observed discrepancies between calculated and experimental results were used in conjunction with the computed sensitivity coefficients and covariance matrix for nuclear parameters in a consistent data assimilation. Only the GODIVA and JEZEBEL experimental results were used, in order to exploit information relative to the isotope of interest that are, in this particular case: 235U and 239Pu. The results obtained by the consistent data assimilation indicate that with reasonable modifications (mostly within the initial standard deviation) it is possible to eliminate the original large discrepancies on the Keff of the two critical configurations. However, some residual discrepancy remains for a few fission spectral indices that are, most likely, to be attributed to the detector cross sections.

  10. Variation in the isotopic content of precipitation with altitude

    Monthly precipitation and single storms have been collected during three years at 12 stations along a W-E profile in Chile, going from Juan Fernandez Islands to Valparaiso, Santiago and Infiernillo in the Andes, and analysed for their deuterium content. The deltaD values are correlated with the altitude of the station, the mean temperature - which also largely depends on the altitude - and the distance from the sea. The correlation parameters show however important variations from year to year and even more from month to month. For instance, in the stretch Santiago (520 m a.s.l.) - La Parva (2680 m) the mean isotopic gradient with altitude were: -1.84 deltaD per mil/100 m in 1970, -1.09 in 1971 and -2.0 in 1972. The low value observed in 1971 could be a consequence of the peculiar weather characteristics of this unusually dry year. In the stretch from the coast to Santiago the trend of the isotopic composition of precipitation is more complicated, because the so-called continental effect is superimposed to the altitude effect. The deuterium content variations have been also determined in snowpack profiles at La Parva station. The results show that snow melting occurs slowly at the bottom during the whole winter, at the expenses of the heat stored during summer in the soil. The melting of the surface snow layers only starts at the end of the winter and then proceeds very fast

  11. Stable isotopes on jumbo squid (Dosidicus gigas) beaks to esitmate its trophic positon: comparison between stomach contents and stable isotopes

    Ruiz Cooley, R.I.; Markaida, U.; Gendron, Diane; Aguíñiga García, Sergio

    2006-01-01

    Stomach contents and carbon (C) and nitrogen (N) stable isotope analysis were used to evaluate trophic relationships of jumbo squid, Dosidicus gigas. Buccal masses, beaks and stomach contents of large and medium maturing-sized jumbo squid and muscle from its main prey, the myctophid Benthosema panamense, were collected in the Gulf of California, Mexico during 1996, 1997 and 1999. Both the quantified C and N-isotope ratios in muscle, and stomach content analysis revealed that larger-sized matu...

  12. Comparative determination of sucrose content in sugar beet by polarimetric and isotope dilution methods

    The comparative determination of sucrose content in sugar beets has been investigated by following methods: polarimetric, direct isotope dilution and double carrier-isotope dilution analysis. Basing upon the obtained results it has been ascertained, that in the case of worse quality beets the polarimetric determinations differ greatly from isotopic data. (author)

  13. Managing Inventories of Heavy Actinides

    The Department of Energy (DOE) has stored a limited inventory of heavy actinides contained in irradiated targets, some partially processed, at the Savannah River Site (SRS) and Oak Ridge National Laboratory (ORNL). The 'heavy actinides' of interest include plutonium, americium, and curium isotopes; specifically 242Pu and 244Pu, 243Am, and 244/246/248Cm. No alternate supplies of these heavy actinides and no other capabilities for producing them are currently available. Some of these heavy actinide materials are important for use as feedstock for producing heavy isotopes and elements needed for research and commercial application. The rare isotope 244Pu is valuable for research, environmental safeguards, and nuclear forensics. Because the production of these heavy actinides was made possible only by the enormous investment of time and money associated with defense production efforts, the remaining inventories of these rare nuclear materials are an important part of the legacy of the Nuclear Weapons Program. Significant unique heavy actinide inventories reside in irradiated Mark-18A and Mark-42 targets at SRS and ORNL, with no plans to separate and store the isotopes for future use. Although the costs of preserving these heavy actinide materials would be considerable, for all practical purposes they are irreplaceable. The effort required to reproduce these heavy actinides today would likely cost billions of dollars and encompass a series of irradiation and chemical separation cycles for at least 50 years; thus, reproduction is virtually impossible. DOE has a limited window of opportunity to recover and preserve these heavy actinides before they are disposed of as waste. A path forward is presented to recover and manage these irreplaceable National Asset materials for future use in research, nuclear forensics, and other potential applications.

  14. Actinides-1981

    1981-09-01

    Abstracts of 134 papers which were presented at the Actinides-1981 conference are presented. Approximately half of these papers deal with electronic structure of the actinides. Others deal with solid state chemistry, nuclear physic, thermodynamic properties, solution chemistry, and applied chemistry.

  15. Actinides-1981

    Abstracts of 134 papers which were presented at the Actinides-1981 conference are presented. Approximately half of these papers deal with electronic structure of the actinides. Others deal with solid state chemistry, nuclear physic, thermodynamic properties, solution chemistry, and applied chemistry

  16. Calorimetric assay of minor actinides

    Rudy, C.; Bracken, D.; Cremers, T.; Foster, L.A.; Ensslin, N.

    1996-12-31

    This paper reviews the principles of calorimetric assay and evaluates its potential application to the minor actinides (U-232-4, Am-241, Am- 243, Cm-245, Np-237). We conclude that calorimetry and high- resolution gamma-ray isotopic analysis can be used for the assay of minor actinides by adapting existing methodologies for Pu/Am-241 mixtures. In some cases, mixtures of special nuclear materials and minor actinides may require the development of new methodologies that involve a combination of destructive and nondestructive assay techniques.

  17. Calorimetric assay of minor actinides

    This paper reviews the principles of calorimetric assay and evaluates its potential application to the minor actinides (U-232-4, Am-241, Am- 243, Cm-245, Np-237). We conclude that calorimetry and high- resolution gamma-ray isotopic analysis can be used for the assay of minor actinides by adapting existing methodologies for Pu/Am-241 mixtures. In some cases, mixtures of special nuclear materials and minor actinides may require the development of new methodologies that involve a combination of destructive and nondestructive assay techniques

  18. Research needs in metabolism and dosimetry of the actinides

    The following topics are discussed: uranium mine and mill tailings; environmental standards; recommendations of NCRP and ICRP; metabolic models and health effects; life-time exposures to actinides and other alpha emitters; high-specific-activity actinide isotopes versus naturally occurring isotopic mixtures of uranium isotopes; adequacy of the n factor; and metabolism and dosimetry;

  19. Substoichiometry and radioactive isotopic dilution determination of trace content of zinc in human's hair and urine

    This experiment has been successfully used in substoichiometry and isotopic dilution for determining trace content of zinc in human's hair and urine. Experimental results are compared with those using others methods

  20. Nuclear data needs for the analysis of generation and burn-up of actinide isotopes in nuclear reactors

    A reliable prediction of the in-pile and out-of-pile physics characteristics of nuclear fuel is one of the objectives of present-day reactor physics. The paper describes the main production paths of important actinides for light water and fast breeder reactors. The accuracy of recent nuclear data is examined by comparisons of theoretical predictions with the results from post-irradiation analysis of nuclear fuel from power reactors, and partly with results obtained in zero-power facilities. A world-wide comparison of nuclear data to be used in large fast power reactor burn-up and long term considerations is presented. The needs for further improvement of nuclear data are discussed. (orig.)

  1. Dietary interpretations for extinct megafauna using coprolites, intestinal contents and stable isotopes: Complimentary or contradictory?

    Rawlence, Nicolas J.; Wood, Jamie R.; Bocherens, Herve; Rogers, Karyne M.

    2016-06-01

    For many extinct species, direct evidence of diet (e.g. coprolites, gizzard/intestinal contents) is not available, and indirect dietary evidence (e.g. stable isotopes) must be relied upon. The Late Holocene fossil record of New Zealand provides a unique opportunity to contrast palaeodietary reconstructions for the extinct moa (Aves: Dinornithiformes) using stable isotopes and coprolite/gizzard contents. Palaeodietary reconstructions from isotopes are found to contradict those based on direct dietary evidence. We discuss reasons for this and advocate, where possible, for the use of multiple lines of evidence in reconstructing the diets of extinct species.

  2. Research on the chemical speciation of actinides

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using advanced laser-based highly sensitive spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been performed for the chemical speciation of actinide in an aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. (1) Development of TRLFS technology for chemical speciation of actinides, (2) Development of LIBD technology for measuring solubility of actinides, (3) Chemical speciation of plutonium complexes by using a LWCC system, (4) Development of LIBS technology for the quantitative analysis of actinides, (5) Development of technology for the chemical speciation of actinides by CE, (6) Evaluation on the chemical reactions between actinides and humic substances, (7) Chemical speciation of actinides adsorbed on metal oxides surfaces, (8) Determination of actinide source terms of spent nuclear fuel

  3. Nuclear data for plutonium and minor actinides

    Some experience in the usage of different evaluations of neutron constants for plutonium isotopes and minor actinides (MA) is described. That experience was obtained under designing the ABBN-93 group data set which nowadays is used widely for neutronics calculations of different cores with different spectrum and shielding. Under testing of the ABBN-93 data set through different integral and macroscopic experiments the main attention was paid to fuel nuclides and cross sections for MA practically did not verify. That gave an opportunity to change MA nuclear data for more modern without verification of the hole system. This desire appeared with new data libraries JENDL-3.2, JEF-2.2 and ENDF/B-6.2, which was not accessible under designing the ABBN-93. At the same time with the reevaluation of the basic MA nuclear data the ABBN-93 and the library FOND-2 of evaluated nuclear data files, which used as the basis for retrieving of the ABBN-93 data, were added with not very important MA data. So the FOND-2 library nowadays contents nuclear data files for all actinides with the half-life time more 1 day and also those MA which produce long-life actinides

  4. Normalisation models for accounting for fat content in stable isotope measurements in salmonid muscle tissue

    Abrantes, K.G.; Semmens, J. M.; Lyle, J.M.; Nichols, P D

    2012-01-01

    Stable isotope analysis is increasingly used in ecological studies. Because lipid content influences d13C, lipids should be removed from lipid-rich samples before d13C analysis. To account for differences in d13C arising from differences in lipid content, relationships between lipid content, C:N ratio and ?d13C with lipid removal can be used to normalise lipid content to uniform levels. We investigate these relationships for salmonid muscle and evaluate the suitability of previously published...

  5. Experimental control of burn-up calculations for high temperature reactor fuel by introduction of a special alpha spectrometric method for the determination of transuranium content. An attempt to establish isotopic correlations

    In the field of high-temperature-reactor (HTR) fuel investigation there is a great interest in the experimental and calculational determination of heavy metal content under the aspects of burn-up physics and for the prediction of reliable data for reprocessing and waste management. Using a laser-micro-boring preparation method, high resolution alpha-spectroscopy and sophisticated computer decomposition programs we identify qualitatively and quantitatively most of the important actinide isotopes in irradiated HTR-fuel. Additionally we use data, delivered by gamma- and mass-spectroscopy of the same fuel samples. The evaluated results are compared with calculational results from the burn-up code ORIGEN, using a special generated HTR-neutron-cross-section library. In a first step we determine new cross sections for the uranium and plutonium isotopes depending on the irradiation conditions. In a second step we calculate correlations between the heavy metal isotopes and the burn-up or the fission products

  6. Sector field inductively coupled plasma mass spectrometry in the elemental and isotopic analysis of lanthanides and actinides

    Plutonium is one element which is indispensable in identifying the source and for estimating the hazardous effects of rad. The isotopic ratios of plutonium (240Pu/239Pu) and its total concentration in environmental samples were also precisely estimated by high resolution inductively coupled plasma mass spectrometry

  7. Radiochemical measurements of the formation cross sections of actinide isotopes in the reaction of 238U ions with 238U

    The method of high-pressure liquid chromatography was used to separate metal cations and anions. Thereby the influence of different parameters on the separation of lanthanides by cation exchange and extraction chromatography was systematically investigated. The results were used to optimize that separation cycle, in which the elements from Z = 26 to Z = 101 were separated taking into account especially the group of actinides. These separations and the subsequent spectroscopy of gamma radiation, alpha particles and spontaneous fission fragments were used to determine formation cross sections in heavy ion reactions as a function of the atomic charge and the mass number. The most important point was the investigation of the collision of 238U ions at different bombarding energies. On the basis of the measured formation cross sections conclusions can be drawn on the reaction mechanism and the excitation function of the formation of transplutonium elements. According to the results it seems to be reasonable to use transfer reactions between 238U and 238U or 248Cm to synthesize superheavy nuclei around Z = 114. Until now that has been tried only with the help of fusion reactions and the results were negative. (orig.)

  8. Isoscaling and fission modes in the yields of the Kr and Xe isotopes from photofission of actinides

    Drnoyan, J.; Zhemenik, V. I.; Mishinsky, G. V.

    2016-05-01

    Yields of Kr and Xe isotopes in photofission of 232Th, 238U, 237Np, 244Pu, 243Am, and 248Cm were tested for isoscaling dependence. Isoscaling for Kr is revealed. For Xe, isoscaling is found to be affected by the STI and STII fission modes governed by the N = 82 and N = 88 neutron shells. The work was performed at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (JINR).

  9. Photochemistry of the actinides

    It has been found that all three major actinides have a useful variety of photochemical reactions which could be used to achieve a separations process that requires fewer reagents. Several features merit enumerating: (1) Laser photochemistry is not now as uniquely important in fuel reprocessing as it is in isotopic enrichment. The photochemistry can be successfully accomplished with conventional light sources. (2) The easiest place to apply photo-reprocessing is on the three actinides U, Pu, and Np. The solutions are potentially cleaner and more amenable to photoreactions. (3) Organic-phase photoreactions are probably not worth much attention because of the troublesome solvent redox chemistry associated with the photochemical reaction. (4) Upstream process treatment on the raffinate (dissolver solution) may never be too attractive since the radiation intensity precludes the usage of many optical materials and the nature of the solution is such that light transmission into it might be totally impossible

  10. Sensitivity of ICP-MS, PERALS and alpha spectrometry for the determination of actinides

    The purpose of this study was to compare the sensitivity of the three most popular techniques for the determination of minor actinides at environmental levels: ICP-MS, PERALS and solid state alpha spectrometry. For each method the limit of detection and the resolution were estimated in order to study the content and isotopic composition of the actinides. The sensitivities of the three determination techniques were compared. Two international reference materials, IAEA-135 (Irish Sea sediment) and IAEA-300 (Baltic Sea sediment) were analyzed for activity concentrations of 238Pu, 239Pu, 240Pu, 241Pu and 241Am. (authors)

  11. The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses

    Dickson, J H; Oeggl, K; Holden, T.G.; Handley, L.L.; O'Connell, T C; Preston, T

    2000-01-01

    The contents of the colon of the Tyrolean Iceman who lived Ga. 5300 years ago include muscle fibres, cereal remains, a diversity of pollen, and most notably that of the hop hornbeam (Ostrya carpinifolia) retaining cellular contents, as well as a moss leaf (Neckera complanata) and eggs of the parasitic whipworm (Trichuris trichiura). Based almost solely on stable isotope analyses and ignoring the work on the colon contents, two recently published papers on the Iceman's diet draw ill- founded c...

  12. Metal Content and Stable Isotope Determination in Some Commercial Beers from Romanian Markets

    Cezara Voica; Dana-Alina Magdas; Ioana Feher

    2015-01-01

    Characterization of beer samples is of interest because their compositions affect the taste and stability of beer and, also, consumer health. In this work, the characterizations of 20 Romanian beers were performed by mean of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Isotope Ratio Mass Spectrometry (IRMS) in order to trace heavy metals and isotopic content of them. Major, minor, and trace metals are important in beer fermentation since they supply the appropriate environment fo...

  13. Anthropogenic Actinides in the Environment

    The use of nuclear energy and the testing of nuclear weapons have led to significant releases of anthropogenic isotopes, in particular a number of actinide isotopes generally not abundant in nature. Most prominent amongst these are 239Pu, 240Pu, and 236U. The study of these actinides in nature has been an active field of study ever since. Measurements of actinides are applied to nuclear safeguards, investigating the sources of contamination, and as a tracer for a number of erosion and hydrology studies. Accelerator Mass Spectrometry (AMS) is ideally suited for these studies and generally offers higher sensitivities than competing techniques, like ICP-MS or decay counting. Recent advances in AMS allow the study of “minor” plutonium isotopes (241Pu, 242Pu, and 244Pu). Furthermore, 236U can now be measured at the levels expected from the global stratospheric fall-out of the atmospheric nuclear weapon tests in the 1950s and 1960s. Even the pre-anthropogenic isotope ratios could be within reach. However, the distribution and abundance levels of these isotopes are not well known yet. I will present an overview of the field, and in detail two recent studies on minor plutonium isotopes and 236U, respectively.(author)

  14. Nitrogen Contents and Isotopic Characteristics of Mesozoic and Cenozoic Granites in Northeastern China

    张成君; 文启彬

    2000-01-01

    The method of determining the nitrogen isotopic composition of granites in the northeastern part of China is described.The content and isotopic values of nitrogen released from granite samples by stepwise heating were determined as well.The results showed that the diferent areas of northeastern China hae a great difference in nitrogen content and isotopic composition.Nitrogen released from the granites is 1.64-6.23μL/g ,with the maximum at about 600℃,from rhyolite and granophyre is 108.98-755.96μL/g,with the maximum at about 900℃,It is proved that fluid is characterized by heterogeneity in the deep crust of the different areas in northeastern China.The nitrogen isotopic compositions in different ranges of temperautes are wweighted.And the nitrogen isotopic compositions in different anges of temperatures are weighted.And the nitrogen isotopic values are +9.2‰ to +17.0‰,with a variation range of 7.8‰,The nitrogen isotopic ratios may have been fractionated during degassing and the fluid released from granites is the residual component.

  15. Actinide recycle

    A multitude of studies and assessments of actinide partitioning and transmutation were carried out in the late 1970s and early 1980s. Probably the most comprehensive of these was a study coordinated by Oak Ridge National Laboratory. The conclusions of this study were that only rather weak economic and safety incentives existed for partitioning and transmuting the actinides for waste management purposes, due to the facts that (1) partitioning processes were complicated and expensive, and (2) the geologic repository was assumed to contain actinides for hundreds of thousands of years. Much has changed in the few years since then. A variety of developments now combine to warrant a renewed assessment of the actinide recycle. First of all, it has become increasingly difficult to provide to all parties the necessary assurance that the repository will contain essentially all radioactive materials until they have decayed. Assurance can almost certainly be provided to regulatory agencies by sound technical arguments, but it is difficult to convince the general public that the behavior of wastes stored in the ground can be modeled and predicted for even a few thousand years. From this point of view alone there would seem to be a clear benefit in reducing the long-term toxicity of the high-level wastes placed in the repository

  16. Isotopic Incorporation and the Effects of Fasting and Dietary Lipid Content on Isotopic Discrimination in Large Carnivorous Mammals.

    Rode, K D; Stricker, C A; Erlenbach, J; Robbins, C T; Cherry, S G; Newsome, S D; Cutting, A; Jensen, S; Stenhouse, G; Brooks, M; Hash, A; Nicassio, N

    2016-01-01

    There has been considerable emphasis on understanding isotopic discrimination for diet estimation in omnivores. However, discrimination may differ for carnivores, particularly species that consume lipid-rich diets. Here, we examined the potential implications of several factors when using stable isotopes to estimate the diets of bears, which can consume lipid-rich diets and, alternatively, fast for weeks to months. We conducted feeding trials with captive brown bears (Ursus arctos) and polar bears (Ursus maritimus). As dietary lipid content increased to ∼90%, we observed increasing differences between blood plasma and diets that had not been lipid extracted (∆(13)Ctissue-bulk diet) and slightly decreasing differences between plasma δ(13)C and lipid-extracted diet. Plasma Δ(15)Ntissue-bulk diet increased with increasing protein content for the four polar bears in this study and data for other mammals from previous studies that were fed purely carnivorous diets. Four adult and four yearling brown bears that fasted 120 d had plasma δ(15)N values that changed by carnivores has minimal effects on δ(13)C and δ(15)N discrimination between predators and their prey but that dietary lipid content is an important factor directly affecting δ(13)C discrimination and indirectly affecting δ(15)N discrimination via the inverse relationship with dietary protein content. PMID:27153128

  17. Absolute measurement of the isotopic ratio of a water sample with very low deuterium content

    The presence of H3+ ions which are indistinguishable from HD+ ions presents the principal difficulty encountered in the measurement of isotopic ratios of water samples with very low deuterium contents using a mass spectrometer. Thus, when the sample contains no deuterium, the mass spectrometer does not indicate zero. By producing, in situ, from the sample to be measured, water vapor with an isotopic ratio very close to zero using a small distilling column, this difficulty is overcome. This column, its operating parameters, as well as the way in which the measurements are made are described. An arrangement is employed in which the isotopic ratios can be measured with a sensitivity better than 0.01 x 10-6. The method is applied to the determination of the isotopic ratios of three low deuterium content water samples. The results obtained permit one to assign to the sample with the lowest deuterium content an absolute value equal to 1.71 ± 0.03 ppm. This water sample is a primary standard from which is determined the isotopic ratio of a natural water sample which serves as the laboratory standard. (author)

  18. Integrating stomach content and stable isotope analyses to quantify the diets of pygoscelid penguins.

    Michael J Polito

    Full Text Available Stomach content analysis (SCA and more recently stable isotope analysis (SIA integrated with isotopic mixing models have become common methods for dietary studies and provide insight into the foraging ecology of seabirds. However, both methods have drawbacks and biases that may result in difficulties in quantifying inter-annual and species-specific differences in diets. We used these two methods to simultaneously quantify the chick-rearing diet of Chinstrap (Pygoscelis antarctica and Gentoo (P. papua penguins and highlight methods of integrating SCA data to increase accuracy of diet composition estimates using SIA. SCA biomass estimates were highly variable and underestimated the importance of soft-bodied prey such as fish. Two-source, isotopic mixing model predictions were less variable and identified inter-annual and species-specific differences in the relative amounts of fish and krill in penguin diets not readily apparent using SCA. In contrast, multi-source isotopic mixing models had difficulty estimating the dietary contribution of fish species occupying similar trophic levels without refinement using SCA-derived otolith data. Overall, our ability to track inter-annual and species-specific differences in penguin diets using SIA was enhanced by integrating SCA data to isotopic mixing modes in three ways: 1 selecting appropriate prey sources, 2 weighting combinations of isotopically similar prey in two-source mixing models and 3 refining predicted contributions of isotopically similar prey in multi-source models.

  19. Research on the chemical speciation of actinides

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using highly sensitive and advanced laser-based spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been applied for the chemical speciation of actinide in aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. Development of TRLFS technology for the chemical speciation of actinides, Development of laser-induced photo-acoustic spectroscopy (LPAS) system, Application of LIBD technology to investigate dynamic behaviors of actinides dissolution reactions, Development of nanoparticle analysis technology in groundwater using LIBD, Chemical speciation of plutonium complexes by using a LWCC system, Development of LIBS technology for the quantitative analysis of actinides, Evaluation on the chemical reactions between actinides and humic substances, Spectroscopic speciation of uranium-ligand complexes in aqueous solution, Chemical speciation of actinides adsorbed on metal oxides surfaces

  20. Actinides analysis by accelerator mass spectrometry

    At the ANTARES accelerator at ANSTO a new beamline has been commissioned, incorporating new magnetic and electrostatic analysers, to optimise the efficiency for Actinides detection by Accelerator Mass Spectrometry (AMS). The detection of Actinides, particularly the isotopic ratios of uranium and plutonium, provide unique signatures for nuclear safeguards purposes. We are currently engaged in a project to evaluate the application of AMS to the measurement of Actinides in environmental samples for nuclear safeguards. Levels of certain fission products, Actinides and other radioactive species can be used as indicators of undeclared nuclear facilities or activities, either on-going or in the past Other applications of ultra-sensitive detection of Actinides are also under consideration. neutron-attenuation images of a porous reservoir rock

  1. Lithium contents and isotopic compositions of ferromanganese deposits from the global ocean

    Chan, L.-H.; Hein, J.R.

    2007-01-01

    To test the feasibility of using lithium isotopes in marine ferromanganese deposits as an indicator of paleoceanographic conditions and seawater composition, we analyzed samples from a variety of tectonic environments in the global ocean. Hydrogenetic, hydrothermal, mixed hydrogenetic–hydrothermal, and hydrogenetic–diagenetic samples were subjected to a two-step leaching and dissolution procedure to extract first the loosely bound Li and then the more tightly bound Li in the Mn oxide and Fe oxyhydroxide. Total leachable Li contents vary from 2 by coulombic force. Hence, the abundant Li in hydrothermal deposits is mainly associated with the dominant phase, MnO2. The surface of amorphous FeOOH holds a slightly positive charge and attracts little Li, as demonstrated by data for hydrothermal Fe oxyhydroxide. Loosely sorbed Li in both hydrogenetic crusts and hydrothermal deposits exhibit Li isotopic compositions that resemble that of modern seawater. We infer that the hydrothermally derived Li scavenged onto the surface of MnO2 freely exchanged with ambient seawater, thereby losing its original isotopic signature. Li in the tightly bound sites is always isotopically lighter than that in the loosely bound fraction, suggesting that the isotopic fractionation occurred during formation of chemical bonds in the oxide and oxyhydroxide structures. Sr isotopes also show evidence of re-equilibration with seawater after deposition. Because of their mobility, Li and Sr in the ferromanganese crusts do not faithfully record secular variations in the isotopic compositions of seawater. However, Li content can be a useful proxy for the hydrothermal history of ocean basins. Based on the Li concentrations of the globally distributed hydrogenetic and hydrothermal samples, we estimate a scavenging flux of Li that is insignificant compared to the hydrothermal flux and river input to the ocean.

  2. Reconstruction of the isotope activity content of heterogeneous nuclear waste drums

    Radioactive waste must be characterized in order to verify its conformance with national regulations for intermediate storage or its disposal. Segmented gamma scanning (SGS) is a most widely applied non-destructive analytical technique for the characterization of radioactive waste drums. The isotope specific activity content is generally calculated assuming a homogeneous matrix and activity distribution for each measured drum segment. However, real radioactive waste drums exhibit non-uniform isotope and density distributions most affecting the reliability and accuracy of activities reconstruction in SGS. The presence of internal shielding structures in the waste drum contributes generally to a strong underestimation of the activity and this in particular for radioactive sources emitting low energy gamma-rays independently of their spatial distribution. In this work we present an improved method to quantify the activity of spatially concentrated gamma-emitting isotopes (point sources or hot spots) in heterogeneous waste drums with internal shielding structures. The isotope activity is reconstructed by numerical simulations and fits of the angular dependent count rate distribution recorded during the drum rotation in SGS using an analytical expression derived from a geometric model. First results of the improved method and enhancements of this method are shown and are compared to each other as well as to the conventional method which assumes a homogeneous matrix and activity distribution. It is shown that the new model improves the accuracy and the reliability of the activity reconstruction in SGS and that the presented algorithm is suitable with respect to the framework requirement of industrial application. - Highlights: ► The reconstruction of the isotope specific activity content relies on an easy analytical model motivated by basic physics. ► The reconstruction of the isotope specific activity content is based on the assumption that activity can be

  3. Linking ramped pyrolysis isotope data to oil content through PAH analysis

    Ramped pyrolysis isotope (13C and 14C) analysis coupled with polycyclic aromatic hydrocarbon (PAH) analysis demonstrates the utility of ramped pyrolysis in screening for oil content in sediments. Here, sediments from Barataria Bay, Louisiana, USA that were contaminated by oil from the 2010 BP Deepwater Horizon spill display relationships between oil contamination, pyrolysis profiles, and isotopic composition. Sediment samples with low PAH concentrations are thermochemically stable until higher temperatures, while samples containing high concentrations of PAHs pyrolyze at low temperatures. High PAH samples are also depleted in radiocarbon (14C), especially in the fractions that pyrolyze at low temperatures. This lack of radiocarbon in low temperature pyrolyzates is indicative of thermochemically unstable, 14C-free oil content. This study presents a proof of concept that oil contamination can be identified by changes in thermochemical stability in organic material and corroborated by isotope analysis of individual pyrolyzates, thereby providing a basis for application of ramped pyrolysis isotope analysis to samples deposited in different environments for different lengths of time. (letter)

  4. ENDF/B-V actinides

    This document summarizes the contents of the actinides part of the ENDF/B-V nuclear data library released by the US National Nuclear Data Center. This library or selective retrievals of it, are available from the IAEA Nuclear Data Section. (author)

  5. Diet of invasive lionfish on hard bottom reefs of the Southeast USA: insights from stomach contents and stable isotopes

    National Oceanic and Atmospheric Administration, Department of Commerce — Stomach contents and stable isotope analyses were used to determine the diet of lionfish in the warm-temperate hard bottom reef community in theSoutheast US...

  6. Value of 236U to actinide-only burnup credit

    The US Department of Energy (DOE) submitted a topical report to the US Nuclear Regulatory Commission (NRC) in May 1995 in order to gain approval of a method for criticality analysis of transport packages that takes account for the change in actinide isotopes with burnup [pressurized water reactors (PWRs) only]. Historically, the NRC has conservatively assumed that the fuel was in its initial conditions (without any burnable absorbers). In order to permit credit for the changes in actinide content, the NRC has required validation of the depletion and criticality codes for spent nuclear fuel, justification of conservative depletion modeling, and finally confirmation measurements before loading. The NRC requested additional information on March 22, 1996. The DOE responded by a revision of the topical report in May 1997. The NRC again responded with another set of requests of additional information in April 1998. In that set of questions, the NRC challenged the use of 236U in burnup credit. Uranium-236 is not found in any significant amount in any available critical experiments. The authors explore the value of 236U to actinide-only burnup credit

  7. Preparation, structure and some properties of boron crystals with different content of 10B and 11B isotopes

    The present work deals with the analysis of data on preparation and investigation of boron with different content of 10B and 11B isotopes. It was established that influence of isotopes on the structure and physical-mechanical properties of boron varies with regard to the type and percentage of an applied isotope. Microhardness of the specimens was measured at room temperatures. Peculiarities of changes observed in the values of microhardness, thermal expansion coefficients and characteristics of the relaxation processes are discussed from the point of view of probable changes in inter-atomic forces created due to substitution of natural boron atoms with their isotopes

  8. Spent nuclear fuel corrosion: The application of ICP-MS to direct actinide analysis

    The ICP-MS technique has been applied to the analysis of the actinide contents of corrodant solutions from experiments performed to study the corrosion of spent nuclear fuel in simulated groundwaters. Analysis was performed directly on the solutions, without employing separation or isotope dilution techniques. The results from two analytical campaigns using natural indium and thorium internal standards are compared. Under both oxic and anoxic conditions, the U contents can be determined with good accuracy and precision. The same applies to Np and Pu under oxic conditions, where the solution concentrations range down to about 0.1 ppb. Under anoxic conditions, where solution concentrations are lower by one or two orders of magnitude, reasonable results for these two actinides can be obtained, but with much lower precision. Direct analysis of Am and Cm, however, gave unsatisfactory results, since the technique is limited by poor measurement statistics and background uncertainty

  9. Ventilation system of actinides handling facility in Oarai-branch of Tohoku University

    We have reported the development of the facility for handling actinides in Tohoku University at the second KAERI-JAERI joint seminar on PIE technology. Actinide isotopes have most hazardous α-radioactivity. Therefore, a specially designed facility is necessary to carry out experimental study for actinide physics and chemistry. In this paper, we will describe the ventilation system and monitoring system for actinide handling facility. (author)

  10. Coordination chemistry for new actinide separation processes

    The amount of wastes and the number of chemical steps can be decreased by replacing the PUREX process extractant (TBP) by, N.N- dialkylamides (RCONR'2). Large amounts of deep underground storable wastes can be stored into sub-surface disposals if the long lived actinide isotopes are removed. Spent nuclear fuels reprocessing including the partitioning of the minor actinides Np, Am, Cm and their transmutation into short half lives fission products is appealing to the public who is not favorable to the deep underground storage of large amounts of long half lived actinide isotopes. In this paper coordination chemistry problems related to improved chemical separations by solvent extraction are presented. 2 tabs.; 4 refs

  11. Nuclear Facility Isotopic Content (NFIC) Waste Management System to provide input for safety envelope definition

    The Westinghouse Savannah River Company (WSRC) is aggressively applying environmental remediation and radioactive waste management activities at the US Department of Energy's Savannah River Site (SRS) to ensure compliance with today's challenging governmental laws and regulatory requirements. This report discusses a computer-based Nuclear Facility Isotopic Content (NFIC) Waste Management System developed to provide input for the safety envelope definition and assessment of site-wide facilities. Information was formulated describing the SRS ''Nuclear Facilities'' and their respective bounding inventories of nuclear materials and radioactive waste using the NFIC Waste Management System

  12. About the possibility of cancer diagnostic by analysis of isotopic content of hydrogen in human fluids

    Full text: Cancer diagnostic is one of the main problems of clinical oncology. We report some results on D/H ratio analysis of urine tests of cancerous patients and healthy humans and discuss the possibility of cancer diagnosis by analysis of isotopic content of hydrogen in human fluids. The urine of healthy humans is enriched in deuterium (-60) - (-82) 0/00 in comparison with the average deuterium content in drinking water of Moscow region (-8) - (-89) 0/00. Our data are in accordance with the previous results, but the difference was much less. The water deuterium content of urine tests of patients with different cancer diseases is depleted in deuterium (-85) - (-96) 0/00 and is diminished or close to the average deuterium content of local drinking water. The analysis of our results and their comparison with other data allowed to make a supposition about accumulation of deuterium in a neoplasm tissue, that produces the depletion in deuterium of human fluids. In that case antineoplastic properties of deuterium depleted water (DDW) can speak about the change of moving direction of deuterium in a human organism. Really, the decrease in deuterium content in human fluids, by replacement of drinking water with DDW, should naturally lead to its diminution in a tumor. (authors)

  13. Boron content and isotopic composition of tektites and impact glasses: Constraints on source regions

    Chaussidon, Marc; Koeberl, Christian

    1995-02-01

    Abundances of Li, Be, and B, as well as boron isotopic compositions, were determined in twenty-seven tektite and impact glass samples, using an ion microprobe. Samples included tektites from the Australasian, North American, and Ivory Coast strewn fields, and Aouelloul and Darwin impact glasses. Variations of B abundance and isotopic composition in a flanged australite were also studied. δ 11B variations of only a few permil were found within the australite flange. The isotopic composition shows no correlation with the B contents or with the distance from the rim of the flange. The mean δ 11B value for the flanged australite is very similar to that of Muong-Nong type tektites (-1.9 ± 1.9‰). Thus, vapor fractionation has been unimportant during tektite formation. This is supported by the observation that B contents and the δ 11B values of the different samples from the Australasian tektite strewn field are not correlated with each other. Most tektites show a rather limited range of δ 11B values (-9.3 ± 1.5 to +2.7 ± 1.5%o), which is small compared to the range observed for common terrestrial rocks (-30 to +40‰). The B abundance and isotopic data can be used to place constraints on the tektite source rocks. Australasian tektites have high B and Li abundances; only clay-rich sediments, such as pelagic and neritic sediments, as well as river and deltaic sediments have B contents (up to 100 ppm) and δ 11B values that are in agreement with the range shown by Australasian tektites (-4.9 to + 1.4‰). 10Be and RbSr data indicate continental crustal source rocks and exclude pelagic and neritic sediments. However, deltaic sediments, e.g., from the Mekong river, which are of continental crustal origin, agree with 10Be, RbSr, and B data, and support a possible source locality close to the coast of SE Indochina in the South China Sea. On the other hand, one bediasite sample has a very high δ 11B value of +15.1 ± 2.1‰, requiring the presence of marine

  14. The lanthanides and actinides

    This paper relates the chemical properties of the actinides to their position in the Mendeleev periodic system. The changes in the oxidation states of the actinides with increasing atomic number are similar to those of the 3d elements. Monovalent and divalent actinides are very similar to alkaline and alkaline earth elements; in the 3+ and 4+ oxidation states they resemble d elements in the respective oxidation states. However, in their highest oxidation states the actinides display their individual properties with only a slight resemblance to d elements. Finally, there is a profound similarity between the second half of the actinides and the first half of the lanthanides

  15. Performance comparison of metallic, actinide burning fuel in lead-bismuth and sodium cooled fast reactors

    Weaver, K.D.; Herring, J.S.; Macdonald, P.E. [Idaho National Engineering and Environment Lab., Advanced Nuclear Energy, Idaho (United States)

    2001-07-01

    Various methods have been proposed to ''incinerate'' or ''transmute'' the current inventory of transuranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years. (author)

  16. Performance Comparison of Metallic, Actinide Burning Fuel in Lead-Bismuth and Sodium Cooled Fast Reactors

    Weaver, Kevan Dean; Herring, James Stephen; Mac Donald, Philip Elsworth

    2001-04-01

    Various methods have been proposed to “incinerate” or “transmutate” the current inventory of trans-uranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non-fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years.

  17. Performance comparison of metallic, actinide burning fuel in lead-bismuth and sodium cooled fast reactors

    Various methods have been proposed to ''incinerate'' or ''transmute'' the current inventory of transuranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years. (author)

  18. Minor actinides transmutation strategies in sodium fast reactors

    In minor actinides transmutation strategies for fast spectrum reactors, different possibilities regarding the core loading are considered. We study both homogeneous patterns (HOM) with various minor actinides (MA) content values and heterogeneous schemes (HET) with higher percentages of MA (Np, Am and Cm) at the periphery of reactor. We analyze the capability of transmutation of each design and the reactivity coefficients such as the Doppler constant, void worth and the fraction of delayed neutrons. The EVOLCODE2 code is the computational tool used in this study. It is based on MCNPX and ORIGEN/ACAB codes and allows carrying out burn-up calculations to get the isotopic evolution of fuel composition. Among the three strategies studied (HOM 2.5 %, HOM 4% and HET 20 %) for a possible design of a Sodium Cooled Fast Breeder Reactor, the one with better transmutation results is the HOM 4%, which shows higher absolute and relative values (12 Kg-MA/TWe, 29% respectively). Concerning transmutation in blankets with 20% MA content, results show a very little or no transmutation values when considering Np, Am and Cm together, though a positive small value for Np and Am is obtained

  19. Uranium content and 235U/238U isotopic ratio in dental porcelain powders determined by neutron activation analysis

    The uranium contents and 235U/238U isotopic ratios in 48 dental porcelain powders of 8 brands marketed in Japan were determined by non-destructive neutron activation analysis. The photopeak counts of 277.6 keV of 239Np formed by the 238U(n,γ)239U (yield to)239Np + β- reaction and at 1.595.2 keV of 140La produced by 235U fission were measured with a Ge(Li) semiconductor detector system to determine the uranium content and 235U/238U isotopic ratio. The results of the analysis are tabulated and their significance discussed. (author)

  20. Isotope composition and uranium content in the rivers Naryn and Mailuu-Suu

    To solve the atomic problem, including the creation of an atomic weapon, one must embark on an intensive exploration and mining of radioactive raw materials, first among which uranium, together with other materials and metals. The acquisition of all these materials has thus been accompanied by the creation of a great deal of production and storage wastes and other refuse from plants, leading to many problems of protecting the environment from radioactive and other hazardous metals and materials. And so, as a result of the extensive mining and processing of radioactive and other raw materials that had been necessary for the atomic industry, in locations like Kara-Balty, Mailuu-Suu, Kavak, Kadamzhay and other places, a series of radioactive and hazardous tailings and dumps has been generated in the Kyrgyz Republic. The toxic ingredients from the dumps migrate and mix together with the ground waters that leach the tailings. However, how these waters migrate both in space and time have not been sufficiently studied; and, so, in general, we cannot forecast the propagation of these hazards. In the usual estimation of the scale of migration from uranium plants, only the total uranium content in the ground water is used. But this does not show natural or technogenic components; and it is obvious that the danger from the plants need only be characterized by the technogenic components. To solve this problem, one can employ the phenomenon where there is a natural separation in the fraction of 234U and 238U present in nature and as a result of technological processes. The essence of this understanding is that, as uranium transitions from solid form into a liquid, such as its dissolution in ground water, it undergoes isotope enrichment, i.e. hydrogenic uranium is enriched with 234U compared to 238U.The essence of this understanding is that, as uranium transitions from solid form into a liquid, such as its dissolution in ground water, it undergoes isotope enrichment, i

  1. Actinide environmental chemistry

    In order to predict release and transport rates, as well as design cleanup and containment methods, it is essential to understand the chemical reactions and forms of the actinides under aqueous environmental conditions. Four important processes that can occur with the actinide cations are: precipitation, complexation, sorption and colloid formation. Precipitation of a solid phase will limit the amount of actinide in solution near the solid phase and have a retarding effect on release and transport rates. Complexation increases the amount of actinide in solution and tends to increase release and migration rates. Actinides can sorb on to mineral or rock surfaces which tends to retard migration. Actinide ions can form or become associated with colloidal sized particles which can, depending on the nature of the colloid and the solution conditions, enhance or retard migration of the actinide. The degree to which these four processes progress is strongly dependent on the oxidation state of the actinide and tends to be similar for actinides in the same oxidation state. In order to obtain information on the speciation of actinides in solution, i.e., oxidation state, complexation form, dissolved or colloidal forms, the use of absorption spectroscopy has become a method of choice. The advent of the ultrasensitive, laser induced photothermal and fluorescence spectroscopies has made possible the detection and study of actinide ions at the parts per billion level. With the availability of third generation synchrotrons and the development of new fluorescence detectors, X-ray absorption spectroscopy (XAS) is becoming a powerful technique to study the speciation of actinides in the environment, particularly for reactions at the solid/solution interfaces. (orig.)

  2. Performance Assessment and Uncertainty Evaluation to Analyze Oxygen-18 Isotopic Content of Nitrate Using Modified Pyrolysis Technique

    A method for measuring d18O content of nitrate has been developed. This involves combusting nitrate salt with activated graphite at 550 degree C for 30 minutes and cooling with a moderate cooling rate. Performance assessment of the whole developed analytical train was made using internationally distributed nitrate isotopes reference materials and real world sample of initial zero-nitrate content. The obtained results proved that the method is suited for handling samples of complicated matrices. Nitrate isotopic contents of some selected nitrate salts were measured using the modified procedure and some other well established methods at two different laboratories in Egypt and Germany. Finally, the uncertainty budget associated with the developed procedure was evaluated using the graphical nested hierarchal approach. Through this work, rapid, reliable, precise, catalyst-free, low-priced and less labor intensive offline pyrolysis technique for measuring O-18 content of nitrate has been modified and implemented

  3. The carbon isotope ratios and contents of mineral elements in leaves of Chinese medicinal plants

    Leaf carbon isotope ratios and 13 kinds of mineral elements were measured on 36 species of common Chinese medicinal plants in a subtropical monsoon forest of Ding Hu Shan in Guangdong Province. The .delta.13C value were from -26.4 to -32.6%, indicating that all of the species belonged the photosynthetic C3 types. The relative lower value of δ13C was observed in the life form of shrubs. The contents of 7 elements (N, P, K, Ca, Na Mg, Si) were dependent upon the species, life form, medicinal function and medicinal part. Herb type medicine and the used medicinal part of leaves or whole plant showed higher levels of above elements than the others. Among the nine groups with different medicinal functions, it was found that more nitrogen was in the leaves of medicinal plants for hemophthisis, hypertension and stomachic troubles, more phosphorus and potassium were in the leaves for cancer and snake bite medicines, but more calcium and magnesium were in the leaves for curing rheumatics. Ferric, aluminium and manganese were the main composition of microelements in leaves. There were higher content of ferric in leaves for hemophthisis medicine, higher zinc in leaves for cold and hypertension medicine, and higher Cup in leaves of stomachic medicine. It was suggested that the pattern of mineral elements in leaves of Chinese medicinal plants reflected the different properties of absorption and accumulation. Some additional effect due to the high content of certain element might be associated with the main function of that medicine

  4. Use of fast reactors for actinide transmutation

    The management of radioactive waste is one of the key issues in today's discussions on nuclear energy, especially the long term disposal of high level radioactive wastes. The recycling of plutonium in liquid metal fast breeder reactors (LMFBRs) would allow 'burning' of the associated extremely long life transuranic waste, particularly actinides, thus reducing the required isolation time for high level waste from tens of thousands of years to hundreds of years for fission products only. The International Working Group on Fast Reactors (IWGFR) decided to include the topic of actinide transmutation in liquid metal fast breeder reactors in its programme. The IAEA organized the Specialists Meeting on Use of Fast Breeder Reactors for Actinide Transmutation in Obninsk, Russian Federation, from 22 to 24 September 1992. The specialists agree that future progress in solving transmutation problems could be achieved by improvements in: Radiochemical partitioning and extraction of the actinides from the spent fuel (at least 98% for Np and Cm and 99.9% for Pu and Am isotopes); technological research and development on the design, fabrication and irradiation of the minor actinides (MAs) containing fuels; nuclear constants measurement and evaluation (selective cross-sections, fission fragments yields, delayed neutron parameters) especially for MA burners; demonstration of the feasibility of the safe and economic MA burner cores; knowledge of the impact of maximum tolerable amount of rare earths in americium containing fuels. Refs, figs and tabs

  5. Boron contents and isotopic compositions of hog manure, selected fertilizers, and water in Minnesota

    Komor, S.C.

    1997-01-01

    Boron-isotope (δ11B) values may be useful as surrogate tracers of contaminants and indicators of water mixing in agricultural settings. This paper characterizes the B contents and isotopic compositions of hog manure and selected fertilizers, and presents δ11B data for ground and surface water from two agricultural areas. Boron concentrations in dry hog manure averaged 61 mg/kg and in commercial fertilizers ranged from below detection limits in some brands of ammonium nitrate and urea to 382 mg/kg in magnesium sulfate. Values of δ11B of untreated hog manure ranged from 7.2 to 11.2o/oo and of N fertilizers were −2.0 to 0.7o/oo. In 22 groundwater samples from a sand-plain aquifer in east-central Minnesota, B concentrations averaged 0.04 mg/L and δ11B values ranged from 2.3 to 41.5o/oo. Groundwater beneath a hog feedlot and a cultivated field where hog manure was applied had B-isotope compositions consistent with the water containing hog-manure leachate. In a 775-km2 watershed with silty-loam soils in southcentral Minnesota: 18 samples of subsurface drainage from corn (Zea mays L.) and soybean (Glycine max L. Merr.) fields had average B concentrations of 0.06 mg/L and δ11B values of 5.3 to 15.1o/oo; 27 stream samples had average B concentrations of 0.05 mg/L and δ11B values of 1.0 to 19.0o/oo; and eight groundwater samples had average B concentrations of 0.09 mg/L and δ11B values of −0.3 to 23.0o/oo. Values of δ11B and B concentrations, when plotted against one another, define a curved mixing trend that suggests subsurface drainage and stream water contain mixtures of B from shallow and deep groundwater.

  6. Influence of bacteria on lanthanide and actinide transfer from specific soil components (humus, soil minerals and vitrified municipal solid waste incinerator bottom ash) to corn plants: Sr-Nd isotope evidence

    Experiments have been performed to test the stability of vitrified municipal solid waste (MSW) incinerator bottom ash under the presence of bacteria (Pseudomonas aeruginosa) and plants (corn). The substratum used for the plant growth was a humus-rich soil mixed with vitrified waste. For the first time, information on the stability of waste glasses in the presence of bacteria and plants is given. Results show that inoculated plant samples contained always about two times higher lanthanide and actinide element concentrations. Bacteria support the element transfer since plants growing in inoculated environment developed a smaller root system but have higher trace element concentrations. Compared with the substratum, plants are light rare earth element (LREE) enriched. The vitrified bottom ash has to some extent been corroded by bacteria and plant activities as indicated by the presence of Nd (REE) and Sr from the vitrified waste in the plants. 87Sr/86Sr and 143Nd/144Nd isotope ratios of plants and soil components allow the identification of the corroded soil components and confirm that bacteria accelerate the assimilation of elements from the vitrified bottom ash. These findings are of importance for landfill disposal scenarios, and similar experiments should be performed in order to better constrain the processes of microbially mediated alteration of the MSW glasses in the biosphere

  7. Rapid determination of actinides in asphalt samples

    A new rapid method for the determination of actinides in asphalt samples has been developed that can be used in emergency response situations or for routine analysis. If a radiological dispersive device, improvised nuclear device or a nuclear accident such as the accident at the Fukushima Nuclear Power Plant in March, 2011 occurs, there will be an urgent need for rapid analyses of many different environmental matrices, including asphalt materials, to support dose mitigation and environmental clean-up. The new method for the determination of actinides in asphalt utilizes a rapid furnace step to destroy bitumen and organics present in the asphalt and sodium hydroxide fusion to digest the remaining sample. Sample preconcentration steps are used to collect the actinides and a new stacked TRU Resin + DGA Resin column method is employed to separate the actinide isotopes in the asphalt samples. The TRU Resin plus DGA Resin separation approach, which allows sequential separation of plutonium, uranium, americium and curium isotopes in asphalt samples, can be applied to soil samples as well. (author)

  8. Report of the panel on practical problems in actinide biology

    Practical problems are classified as the need to make operational decisions, the need for regulatory assessment either of individual facilities or of generic actions, and the overt appearance of radiobiological effects in man or radioactivity in man or the environment. Topics discussed are as follows: simulated reactor accident; long term effects of low doses; effects of repeated exposures to actinides; inhaled uranium mine air contaminants; metabolism and dosimetry; environmental equilibrium models; patterns of alpha dosimetry; internal dose calculations; interfaces between actinide biology and environmental studies; removal of actinides deposited in the body; and research needs related to uranium isotopes

  9. Research in actinide chemistry

    This research studies the behavior of the actinide elements in aqueous solution. The high radioactivity of the transuranium actinides limits the concentrations which can be studied and, consequently, limits the experimental techniques. However, oxidation state analogs (trivalent lanthanides, tetravalent thorium, and hexavalent uranium) do not suffer from these limitations. Behavior of actinides in the environment are a major USDOE concern, whether in connection with long-term releases from a repository, releases from stored defense wastes or accidental releases in reprocessing, etc. Principal goal of our research was expand the thermodynamic data base on complexation of actinides by natural ligands (e.g., OH-, CO32-, PO43-, humates). The research undertakes fundamental studies of actinide complexes which can increase understanding of the environmental behavior of these elements

  10. Feasibility studies of actinide recycle in LMFBRs as a waste management alternative

    A strategy of actinide burnup in LMFBRs is being investigated as a waste management alternative to long term storage of high level nuclear waste. This strategy is being evaluated because many of the actinides in the waste from spent-fuel reprocessing have half-lives of thousands of years and an alternative to geological storage may be desired. From a radiological viewpoint, the actinides and their daughters dominate the waste hazard for decay times beyond about 400 years. Actinide burnup in LMFBRs may be an attractive alternative to geological storage because the actinides can be effectively transmuted to fission products which have significantly shorter half-lives. Actinide burnup in LMFBRs rather than LWRs is preferred because the ratio of fission reaction rate to capture reaction rate for the actinides is higher in an LMFBR, and an LMFBR is not so sensitive to the addition of the actinide isotopes. An actinide target assembly recycle scheme is evaluated to determine the effects of the actinides on the LMFBR performance, including local power peaking, breeding ratio, and fissile material requirements. Several schemes are evaluated to identify any major problems associated with reprocessing and fabrication of recycle actinide-containing assemblies. The overall efficiency of actinide burnout in LMFBRs is evaluated, and equilibrium cycle conditions are determined. It is concluded that actinide recycle in LMFBRs offers an attractive alternative to long term storage of the actinides, and does not significantly affect the performance of the host LMFBR. Assuming a 0.1 percent or less actinide loss during reprocessing, a 0.1 percent loss of less during fabrication, and proper recycle schemes, virtually all of the actinides produced by a fission reactor economy could be transmuted in fast reactors

  11. Actinide and fission product evolution benchmarking with Vandellos II (PWR-Spain) measured isotopic values with considering all the burn-up history with consecutive calculation

    At this study, isotopic evolution of the sample E58-263 of assembly WZR0058 of Vandellos Unit II (PWR-Spain) is calculated with MONTEBURNS code system. The sample was exposed with different neutron spectrum because of its different core location at fuel different cycles. At fuel calculation, all fuel cycle burn-up history of Use sample is 1 considered consecutively by using the 'remove' and 'add' option of the MONTEBURNS code. The calculated results are compared with fuel measurement and with cycle by cycle calculation methodology results.

  12. The Lawrence Livermore National Laboratory Intelligent Actinide Analysis System

    The authors have developed an Intelligent Actinide Analysis System (IAAS) for Materials Management to use in the Plutonium Facility at the Lawrence Livermore National Laboratory. The IAAS will measure isotopic ratios for plutonium and other actinides non-destructively by high-resolution gamma-ray spectrometry. This system will measure samples in a variety of matrices and containers. It will provide automated control of many aspects of the instrument that previously required manual intervention and/or control. The IAAS is a second-generation instrument, based on the authors' experience in fielding gamma isotopic systems, that is intended to advance non-destructive actinide analysis for nuclear safeguards in performance, automation, ease of use, adaptability, systems integration and extensibility to robotics. It uses a client-server distributed monitoring and control architecture. The IAAS uses MGA3 as the isotopic analysis code. The design of the IAAS reduces the need for operator intervention, operator training, and operator exposure

  13. The Lawrence Livermore National Laboratory Intelligent Actinide Analysis System

    The authors have developed an Intelligent Actinide Analysis System (IAAS) for Materials Management to use in the Plutonium Facility at the Lawrence Livermore National Laboratory. The IAAS will measure isotopic ratios for plutonium and other actinides non-destructively by high-resolution gamma-ray spectrometry. This system will measure samples in a variety of matrices and containers. It will provide automated control of many aspects of the instrument that previously required manual intervention and/or control. The IAAS is a second-generation instrument, based on experience in fielding gamma isotopic systems, that is intended to advance non-destructive actinide analysis for nuclear safeguards in performance, automation, ease of use, adaptability, systems integration and extensibility to robotics. It uses a client-server distributed monitoring and control architecture. The IAAS uses MGA as the isotopic analysis code. The design of the IAAS reduces the need for operator intervention, operator training, and operator exposure

  14. ENDF/B-5 Actinides (Rev. 86)

    This document summarizes the contents of the Actinides part of the ENDF/B-5 nuclear data library released by the US National Nuclear Data Center. This library or selective retrievals of it, are available costfree from the IAEA Nuclear Data Section upon request. The present version of the library is the Revision of 1986. (author). Refs, figs and tabs

  15. Deuterium content of European palaeowaters as inferred from isotopic composition of fluid inclusions trapped in carbonate cave deposits

    The results of isotope investigations of groundwaters and carbonate cave deposits collected in karstic regions of southern and central Poland are discussed in detail. Combined isotope studies of carbonate cave deposits allowed some important conclusions to be formulated regarding climatic and environmental conditions prevailing over the European continent during the last 300,000 years: (a) δD values of fluid inclusions suggest a remarkable constancy of the heavy isotope content of European palaeoinfiltration waters recharged during interglacial periods, (b) climate-induced, long term changes in isotopic composition of precipitation and surface air temperature over Europe can be characterized by the deuterium gradient of about 1.4 per mille per deg. C, (c) an apparent constancy of the continental gradient in deuterium content of European palaeoinfiltration waters, as judged from fluid inclusion data, and its similarity to the present-day gradient suggests that atmospheric circulation over Europe has not undergone substantial changes during the last 300,000 years. (author). 28 refs, 4 figs, 1 tab

  16. The practice of the direct isotopic dilution method of determining the sucrose content in sugar beet digestion liquids

    In order to determine the actual sucrose content of sugar beet digestion liquids a new modification of the direct isotopic dilution method was worked out, which is easier to perform than the existing modifications. With the aid of sucrose standard solutions and samples of sucrose, glucose, fructose and raffinose in hydrous lead acetate solutions the degree of accuracy of the method was determined, which is better than +- 2%. During the 1973/74 campaign the direct isotopic dilution method was used for determining the actual sucrose content of sugar beet digestion liquids and the measuring results were compared with results of polarimetric determinations. With digestion liquids taken from healthy beet material it was found that the radioactive and polarimetric measuring results agreed well. With digestion fluids from purifying sugar beets having a lower sucrose level, however, there resulted differences between the measuring results of the two methods mentioned which were considerably greater than those dependent on error limits. (orig.)

  17. Radionuclide content and state of isotopic disequilibrium in some utilized smoking pastes

    Shabana, El-Said Ibrahim; Yahya, Ahmad Abu Bakre [King Abdulaziz Univ., Jeddah (Saudi Arabia). Faculty of Engineering, Radiation Protection and Training Centre; Kinsara, Abdulraheem Abdulrahman [King Abdulaziz Univ., Jeddah (Saudi Arabia). Faculty of Engineering, Nuclear Engineering Dept.

    2014-10-01

    {sup 238}U, {sup 234}U, {sup 226}Ra, {sup 210}Pb and {sup 210}Po were measured in some jurak and mehassel samples collected from the local market. Jurak is a paste mixture composed of 30% tobacco, 50% molasses and 20% spices and minced fruits. Mehassel is a local trade-name of a paste mixture of unknown ratios of tobacco to spices and minced fruits. Both jurak and mehassel are used for smoking by Shisha (a pipe used for smoking and has a water filter). Just for comparison, these radionuclides were measured in some cigarette tobacco samples. In cigarette tobacco samples, the average activity concentrations were 0.32 ± 0.10, 0.51 ± 0.11, 3.6 ± 1.0, 16.1 ± 2.4 and 15.8 ± 2.2 Bq/kg for {sup 238}U, {sup 234}U, {sup 226}Ra, {sup 210}Pb and {sup 210}Po, respectively. These values for the same isotopes were 1.01 ± 0.25, 1.04 ± 0.27, 1.2 ± 0.4, 4.4 ± 1.0 and 4.2 ± 0.9 Bq/kg in jurak samples and 0.17 ± 0.07, 0.24 ± 0.08, 1.8 ± 0.7, 7.5 ± 1.7 and 7.0 ± 1.6 Bq/kg in mehassel samples, respectively. Generally, the mean values of the results indicated that, except for uranium in jurak, the activity concentration for all the analyzed radionuclides in the different samples followed the sequence: {sup 210}Po ∼ {sup 210}Pb > {sup 226}Ra >> {sup 234}U > {sup 238}U, whereas for each radionuclide, its activity concentration followed the sequence: cigarette tobacco > mehassel > jurak. Molasses contributed to the enhanced uranium content in jurak samples. The obtained results are discussed in detail.

  18. Radionuclide content and state of isotopic disequilibrium in some utilized smoking pastes

    238U, 234U, 226Ra, 210Pb and 210Po were measured in some jurak and mehassel samples collected from the local market. Jurak is a paste mixture composed of 30% tobacco, 50% molasses and 20% spices and minced fruits. Mehassel is a local trade-name of a paste mixture of unknown ratios of tobacco to spices and minced fruits. Both jurak and mehassel are used for smoking by Shisha (a pipe used for smoking and has a water filter). Just for comparison, these radionuclides were measured in some cigarette tobacco samples. In cigarette tobacco samples, the average activity concentrations were 0.32 ± 0.10, 0.51 ± 0.11, 3.6 ± 1.0, 16.1 ± 2.4 and 15.8 ± 2.2 Bq/kg for 238U, 234U, 226Ra, 210Pb and 210Po, respectively. These values for the same isotopes were 1.01 ± 0.25, 1.04 ± 0.27, 1.2 ± 0.4, 4.4 ± 1.0 and 4.2 ± 0.9 Bq/kg in jurak samples and 0.17 ± 0.07, 0.24 ± 0.08, 1.8 ± 0.7, 7.5 ± 1.7 and 7.0 ± 1.6 Bq/kg in mehassel samples, respectively. Generally, the mean values of the results indicated that, except for uranium in jurak, the activity concentration for all the analyzed radionuclides in the different samples followed the sequence: 210Po ∼ 210Pb > 226Ra >> 234U > 238U, whereas for each radionuclide, its activity concentration followed the sequence: cigarette tobacco > mehassel > jurak. Molasses contributed to the enhanced uranium content in jurak samples. The obtained results are discussed in detail.

  19. Environmental forcing does not induce diel or synoptic variation in carbon isotope content of forest soil respiration

    Bowling, D. R.; Egan, J E; S.J. Hall; D. A. Risk

    2015-01-01

    Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C) of CO2 produced by respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature) and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation). We used an extensive suite of measurements to examine soil respiration over two months in a subalpine...

  20. Environmental forcing does not induce diel or synoptic variation in the carbon isotope content of forest soil respiration

    Bowling, D. R.; Egan, J E; S.J. Hall; D. A. Risk

    2015-01-01

    Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C) of CO2 produced by the respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature) and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation). We used an extensive suite of measurements to examine soil respiration over 2 months in a subalpine fore...

  1. Research in actinide chemistry

    1991-01-01

    This report contains research results on studies of inorganic and organic complexes of actinide and lanthanide elements. Special attention is given to complexes of humic acids and to spectroscopic studies.

  2. PF-4 actinide disposition strategy

    The dwindling amount of Security Category I processing and storage space across the DOE Complex has driven the need for more effective storage of nuclear materials at LANL's Plutonium Facility's (PF-4's) vault. An effort was begun in 2009 to create a strategy, a roadmap, to identify all accountable nuclear material and determine their disposition paths, the PF-4 Actinide Disposition Strategy (PADS). Approximately seventy bins of nuclear materials with similar characteristics - in terms of isotope, chemical form, impurities, disposition location, etc. - were established in a database. The ultimate disposition paths include the material to remain at LANL, disposition to other DOE sites, and disposition to waste. If all the actions described in the document were taken, over half of the containers currently in the PF-4 vault would been eliminated. The actual amount of projected vault space will depend on budget and competing mission requirements, however, clearly a significant portion of the current LANL inventory can be either dispositioned or consolidated.

  3. Near-IR laser-based spectrophotometer for comparative analysis of isotope content of CO2 in exhale air samples

    We present a laser spectrophotometer aimed at high-accuracy comparative analysis of content of 12CO2 and 13CO2 isotope modifications in the exhale air samples and based on a tunable near-IR diode laser (2.05 μm). The two-channel optical scheme of the spectrophotometer and the special digital system for its control are described. An algorithm of spectral data processing aimed at determining the difference in the isotope composition of gas mixtures is proposed. A few spectral regions (near 4880 cm-1) are determined to be optimal for analysis of relative content of 12CO2 and 13CO2 in the exhale air. The use of the proposed spectrophotometer scheme and the developed algorithm makes the results of the analysis less susceptible to the influence of the interference in optical elements, to the absorption in the open atmosphere, to the slow drift of the laser pulse envelope, and to the offset of optical channels. The sensitivity of the comparative analysis of the isotope content of CO2 in exhale air samples, achieved using the proposed scheme, is estimated to be nearly 0.1‰.

  4. Determination of dependence between physical clay content in sod-podzolic soils and specific activity of 40K natural isotope

    In the conditions of the Republic of Belarus there was analyzed the dependence between physical clay content in sod-podzolic soil and specific activity of 40K natural isotope. There was described a new method of determination of soil belonging to a particular soil type in the conditions of identification of the natural isotope K40. Experiments were realized on sod-podzolic automorphous and half-hydromorphic soils of natural and cultural agrocoenosis polluted with 137Cs and 90Sr after the Chernobyl disaster. The pollution density of 137Cs was from 313 to 2480 kBq/m2 and 90Sr – from 2 to 63 kBq/m2. Research results showed that soil texture content influenced on radionuclide fixation. Radionuclide entering into plants from sod-podzolic loamy soils was in 1,5-2,0 times and more lower in comparison with radionuclide entering from sod-podzolic sandy soils. The highest base exchange capacity of 137Cs, 90Sr and 40K was typical for the fraction of physical clay with the minimal particle size of 0,01mm. There was marked a close correlation connection between natural isotope 40K and a content of physical clay

  5. Minior Actinide Doppler Coefficient Measurement Assessment

    Nolan E. Hertel; Dwayne Blaylock

    2008-04-10

    The "Minor Actinide Doppler Coefficient Measurement Assessment" was a Department of Energy (DOE) U-NERI funded project intended to assess the viability of using either the FLATTOP or the COMET critical assembly to measure high temperature Doppler coefficients. The goal of the project was to calculate using the MCNP5 code the gram amounts of Np-237, Pu-238, Pu-239, Pu-241, AM-241, AM-242m, Am-243, and CM-244 needed to produce a 1E-5 in reactivity for a change in operating temperature 800C to 1000C. After determining the viability of using the assemblies and calculating the amounts of each actinide an experiment will be designed to verify the calculated results. The calculations and any doncuted experiments are designed to support the Advanced Fuel Cycle Initiative in conducting safety analysis of advanced fast reactor or acceoerator-driven transmutation systems with fuel containing high minor actinide content.

  6. Subsurface Biogeochemistry of Actinides

    Kersting, Annie B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Univ. Relations and Science Education; Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst.

    2016-06-29

    A major scientific challenge in environmental sciences is to identify the dominant processes controlling actinide transport in the environment. It is estimated that currently, over 2200 metric tons of plutonium (Pu) have been deposited in the subsurface worldwide, a number that increases yearly with additional spent nuclear fuel (Ewing et al., 2010). Plutonium has been shown to migrate on the scale of kilometers, giving way to a critical concern that the fundamental biogeochemical processes that control its behavior in the subsurface are not well understood (Kersting et al., 1999; Novikov et al., 2006; Santschi et al., 2002). Neptunium (Np) is less prevalent in the environment; however, it is predicted to be a significant long-term dose contributor in high-level nuclear waste. Our focus on Np chemistry in this Science Plan is intended to help formulate a better understanding of Pu redox transformations in the environment and clarify the differences between the two long-lived actinides. The research approach of our Science Plan combines (1) Fundamental Mechanistic Studies that identify and quantify biogeochemical processes that control actinide behavior in solution and on solids, (2) Field Integration Studies that investigate the transport characteristics of Pu and test our conceptual understanding of actinide transport, and (3) Actinide Research Capabilities that allow us to achieve the objectives of this Scientific Focus Area (SFA and provide new opportunities for advancing actinide environmental chemistry. These three Research Thrusts form the basis of our SFA Science Program (Figure 1).

  7. Actinide measurements by AMS using fluoride matrices

    Cornett, R. J.; Kazi, Z. H.; Zhao, X.-L.; Chartrand, M. G.; Charles, R. J.; Kieser, W. E.

    2015-10-01

    Actinides can be measured by alpha spectroscopy (AS), mass spectroscopy or accelerator mass spectrometry (AMS). We tested a simple method to separate Pu and Am isotopes from the sample matrix using a single extraction chromatography column. The actinides in the column eluent were then measured by AS or AMS using a fluoride target matrix. Pu and Am were coprecipitated with NdF3. The strongest AMS beams of Pu and Am were produced when there was a large excess of fluoride donor atoms in the target and the NdF3 precipitates were diluted about 6-8 fold with PbF2. The measured concentrations of 239,240Pu and 241Am agreed with the concentrations in standards of known activity and with two IAEA certified reference materials. Measurements of 239,240Pu and 241Am made at A.E. Lalonde AMS Laboratory agree, within their statistical uncertainty, with independent measurements made using the IsoTrace AMS system. This work demonstrated that fluoride targets can produce reliable beams of actinide anions and that the measurement of actinides using fluorides agree with published values in certified reference materials.

  8. Winter diets of immature green turtles (Chelonia mydas) on a northern feeding ground: integrating stomach contents and stable isotope analyses

    Williams, Natalie C.; Bjorndal, Karen A.; Lamont, Margaret M.; Carthy, Raymond R.

    2015-01-01

    The foraging ecology and diet of the green turtle, Chelonia mydas, remain understudied, particularly in peripheral areas of its distribution. We assessed the diet of an aggregation of juvenile green turtles at the northern edge of its range during winter months using two approaches. Stomach content analyses provide a single time sample, and stable isotope analyses integrate diet over a several-month period. We evaluated diet consistency in prey choice over time by comparing the results of these two approaches. We examined stomach contents from 43 juvenile green turtles that died during cold stunning events in St. Joseph Bay, Florida, in 2008 and 2011. Stomach contents were evaluated for volume, dry mass, percent frequency of occurrence, and index of relative importance of individual diet items. Juvenile green turtles were omnivorous, feeding primarily on seagrasses and tunicates. Diet characterizations from stomach contents differed from those based on stable isotope analyses, indicating the turtles are not feeding consistently during winter months. Evaluation of diets during warm months is needed.

  9. Hydrogeological investigations in the Harwell region: the use of environmental isotopes, inert gas contents, and the uranium decay series

    A comprehensive range of environmental isotopes, radioelement and dissolved gas contents have been measured in groundwaters from the high permeability formations of the Harwell area. These analyses were undertaken as part of a hydrochemical validation of groundwater circulation patterns derived from potentiometric data. These investigations have focused upon the Corallian and Great Oolite formations since these sandwich the Oxford Clay. Geochemical, isotopic, radioelement and inert gas studies have demonstrated consistent trends which substantiate fluid migration patterns derived from hydraulic considerations. Groundwaters at downdip localities in both the Corallian and Great Oolite formations are the oldest waters sampled from the region. Variations in trends in parameters can be attributed to cross-formational flow and subsequent mixing of groundwaters. Individually these techniques can only provide limited information, but the combination of methods used have provided corroborative evidence concerning the direction of fluid circulation in the Harwell region. (author)

  10. Biological pathways and chemical behavior of plutonium and other actinides in the environment

    The principal long-lived actinide elements that may enter the environment from either U or Pu fuel cycles are Pu, Am, Cm, and Np. Approximately 25% of the alpha activity estimated to be released to the atmosphere from the LMFBR fuel cycle will be contributed by 241Am, 242Cm, and 244Cm. The balance of the alpha activity will come from Pu isotopes. Activities of 242Cm, 244Cm, 241Am, 243Am, and 237Np in waste may exceed concentrations of Pu isotopes in waste after various periods of decay. Thorium and uranium isotopes may also be released by operations of the thorium fuel cycle. Environmental actinides are discussed under the following headings: sources of man-made actinide elements; pathways of exposure; environmental chemistry of actinides; uptake of actinides by plants; distribution of actinides in components of White Oak Lake; entry of actinides into terrestrial food chains; relationship between chemical behavior and uptake of actinides by organisms; and behavior of Pu in freshwater and marine food chains

  11. Sources of variability and comparability between salmonid stomach contents and isotopic analyses: study design lessons and recommendations

    Vinson, M.R.; Budy, P.

    2011-01-01

    We compared sources of variability and cost in paired stomach content and stable isotope samples from three salmonid species collected in September 2001–2005 and describe the relative information provided by each method in terms of measuring diet overlap and food web study design. Based on diet analyses, diet overlap among brown trout, rainbow trout, and mountain whitefish was high, and we observed little variation in diets among years. In contrast, for sample sizes n ≥ 25, 95% confidence interval (CI) around mean δ15Ν and δ13C for the three target species did not overlap, and species, year, and fish size effects were significantly different, implying that these species likely consumed similar prey but in different proportions. Stable isotope processing costs were US$12 per sample, while stomach content analysis costs averaged US$25.49 ± $2.91 (95% CI) and ranged from US$1.50 for an empty stomach to US$291.50 for a sample with 2330 items. Precision in both δ15Ν and δ13C and mean diet overlap values based on stomach contents increased considerably up to a sample size of n = 10 and plateaued around n = 25, with little further increase in precision.

  12. Analyses of stomach contents and stable isotopes reveal food sources of estuarine detritivorous fish in tropical/subtropical Taiwan

    Lin, Hsing-Juh; Kao, Wen-Yuan; Wang, Ya-Ting

    2007-07-01

    Detritivorous fish generally refers to fish that primarily ingest unidentified organic detritus. We analyzed stomach contents in combination with stable isotopes to trace and compare the food sources of the large-scale mullet Liza macrolepis and other detritivorous fish species in subtropical mangrove creeks and a tropical lagoon in Taiwan. The volume of organic detritus always contributed >50% of the stomach content of L. macrolepis in the two habitats. However, consumed items were distinct between the two habitats and corresponded to the types in which they reside. The consumed items in the lagoon were more diverse than those observed in the mangroves. In the mangroves, the diet composition of L. macrolepis was primarily determined by season, not by body size. In the lagoon, there were no clear seasonal or size-dependent grouping patterns for the diet composition. There were significant seasonal and spatial variations in δ13C and δ15N values of potential food sources and L. macrolepis. However, neither δ13C nor δ15N values of L. macrolepis were correlated with fish body size. Joint analyses of stomach contents and stable isotopes indicated that benthic microalgae on sediments were the most important assimilated food in both seasons for the dominant detritivorous fish in the mangroves, whereas a greater reliance on microalgal and macroalgal periphyton on oyster-culture pens was observed in the lagoon. Mangrove and marsh plants and phytoplankton, which are mostly locally produced within each habitat, were of minor importance in the assimilated food.

  13. Actinides at the crossroads: ICP-MS or alpha spectrometry?

    The report contains viewgraphs only that summarize the following: Why turn to mass spectrometry for radiochemical measurements; What might be some advantages of using ICP mass spectrometry; Sensitivity of ETV-ICP-MS relative to decay counting (versus half-life); ICP-MS instrument detection limits for dissolved actinide isotopes; Effect of dissolved solids on USN-ICP-MS analysis; Polyatomic ion interferences in ICP-MS actinide measurements; Effect of operating conditions on uranium and protonated uranium signal; ICP mass spectrometry performance in actinide determinations; Determination of actinide elements in soil; Leachable Th-230 and Pu-239 in soil as determined by ICP-MS and alpha spectrometry; Leachable U-234 and U-238 in soil by ICP-MS and alpha spectrometry; Determination of uranium isotopic composition on smears; Activity ratios (U-234/U-238) as determined by mass spectrometry and alpha spectrometry; Uranium isotopic abundances as determined by TIMS and ICP-MS; and Comparison of uranium atom percentages determined by TIMS and ICP-MS. It is concluded that isotope dilution and radiochemical preparative techniques work well in radioanalytical applications of ICP-MS; radioanalytical ICP-MS data are equivalent to data from standard methods (TIMS, alpha spectrometry); and applications in radiation protection and earth sciences are certain to expand further

  14. Radiochemistry and actinide chemistry

    The analysis of trace amounts of actinide elements by means of radiochemistry, is discussed. The similarities between radiochemistry and actinide chemistry, in the case of species amount by cubic cm below 1012, are explained. The parameters which allow to define what are the observable chemical reactions, are given. The classification of radionuclides in micro or macrocomponents is considered. The validity of the mass action law and the partition function in the definition of the average number of species for trace amounts, is investigated. Examples illustrating the results are given

  15. A review of volatile compounds in tektites, and carbon content and isotopic composition of moldavite glass

    Žák, Karel; Skála, Roman; Řanda, Zdeněk; Mizera, Jiří

    2012-01-01

    Roč. 47, č. 6 (2012), s. 1010-1028. ISSN 1086-9379 R&D Projects: GA ČR GA205/09/0991 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z10480505 Keywords : moldavites * geochemistry * ries * carbon stable isotopes * moldavites (Germany) Subject RIV: DD - Geochemistry Impact factor: 2.800, year: 2012

  16. Contents and sulphur isotope composition of trace sulphate and sulphide in various rock types

    The in vacuo Kiba extraction technique for trace sulphate and sulphide has been extended to a variety of rocks including some altered granites provided by the Canadian Nuclear Fuel Waste Management Programme. Although the technique requires considerable development, it shows promise for determining the redox conditions, temperature, and the sulphur isotope composition of dissolved species in fluids involved in initial mineralization and subsequent alteration processes. This may in turn be used to identify sources of sulphur in fluids and provide information about long term weathering of resistant rocks. Preliminary concentration and sulphur isotope data for altered granite samples from the Underground Research Laboratory, Whiteshell, Manitoba suggest that sulphur of other than igneous origin is minor or absent. (author)

  17. Actinide separative chemistry

    Actinide separative chemistry has focused very heavy work during the last decades. The main was nuclear spent fuel reprocessing: solvent extraction processes appeared quickly a suitable, an efficient way to recover major actinides (uranium and plutonium), and an extensive research, concerning both process chemistry and chemical engineering technologies, allowed the industrial development in this field. We can observe for about half a century a succession of Purex plants which, if based on the same initial discovery (i.e. the outstanding properties of a molecule, the famous TBP), present huge improvements at each step, for a large part due to an increased mastery of the mechanisms involved. And actinide separation should still focus R and D in the near future: there is a real, an important need for this, even if reprocessing may appear as a mature industry. We can present three main reasons for this. First, actinide recycling appear as a key-issue for future nuclear fuel cycles, both for waste management optimization and for conservation of natural resource; and the need concerns not only major actinide but also so-called minor ones, thus enlarging the scope of the investigation. Second, extraction processes are not well mastered at microscopic scale: there is a real, great lack in fundamental knowledge, useful or even necessary for process optimization (for instance, how to design the best extracting molecule, taken into account the several notifications and constraints, from selectivity to radiolytic resistivity?); and such a need for a real optimization is to be more accurate with the search of always cheaper, cleaner processes. And then, there is room too for exploratory research, on new concepts-perhaps for processing quite new fuels- which could appear attractive and justify further developments to be properly assessed: pyro-processes first, but also others, like chemistry in 'extreme' or 'unusual' conditions (supercritical solvents, sono-chemistry, could be

  18. Ten years of experience in extraction chromatographic processes for the recovery, separation and purification of actinides elements

    Ten years ago the extraction chromatographic technique was developed for preparative purposes and is now applied for all chemicals separations needed for the production of actinides isotopes. That technique appears to be simple and flexible. It can be used for the production of microgram to kilogram amounts of actinide isotopes. This paper focuses on the experience gained and describes some peculiar production of actinide isotopes solved by using extraction chromatographic technique. After a review of extracting molecules and equipment, treatment of irradiated targets (preparation of Pu 238 and removal of neptunium, production of Am 243 and Cm 244), recovery of actinides from alpha aqueous wastes (preparation of Am 241) and recovery of decay products from aged actinide stocks (recovery of Am 241 from Pu stocks, of U 234 from Pu 238 stocks) are described

  19. Status of nuclear data for actinides

    Guzhovskii, B.Y.; Gorelov, V.P.; Grebennikov, A.N. [Russia Federal Nuclear Centre, Arzamas (Russian Federation)] [and others

    1995-10-01

    Nuclear data required for transmutation problem include many actinide nuclei. In present paper the analysis of neutron fission, capture, (n,2n) and (n,3n) reaction cross sections at energy region from thermal point to 14 MeV was carried out for Th, Pa, U, Np, Pu, Am and Cm isotops using modern evaluated nuclear data libraries and handbooks of recommended nuclear data. Comparison of these data indicates on substantial discrepancies in different versions of files, that connect with quality and completeness of original experimental data.

  20. Compilation of actinide neutron nuclear data

    The Swedish nuclear data committee has compiled a selected set of neutron cross section data for the 16 most important actinide isotopes. The aim of the report is to present available data in a comprehensible way to allow a comparison between different evaluated libraries and to judge about the reliability of these libraries from the experimental data. The data are given in graphical form below about 1 ev and above about 10 keV shile the 2200 m/s cross sections and resonance integrals are given in numerical form. (G.B.)

  1. Physics studies of higher actinide consumption in an LMR

    Hill, R.N.; Wade, D.C.; Fujita, E.K.; Khalil, H.S.

    1990-01-01

    The core physics aspects of the transuranic burning potential of the Integral Fast Reactor (IFR) are assessed. The actinide behavior in fissile self-sufficient IFR closed cycles of 1200 MWt size is characterized, and the transuranic isotopics and risk potential of the working inventory are compared to those from a once-through LWR. The core neutronic performance effects of rare-earth impurities present in the recycled fuel are addressed. Fuel cycle strategies for burning transuranics from an external source are discussed, and specialized actinide burner designs are described. 4 refs., 4 figs., 3 tabs.

  2. Influence of thermal maturity on the hydrogen isotope content of extractable hydrocarbons

    Radke, J.; Bechtel, A.; Püttmann, W.; Gleixner, G.

    2003-04-01

    Based on hydrogen isotope analysis of hydrocarbons from recent sediments it is suggested that compound specific hydrogen isotope ratios are a new proxy to reconstruct the palaeoclimate (Sauer et al., 2001). However, it remains unclear if transformation of carbon bound hydrogen with environmental water during maturation or thermal methanogenesis might influence the observed values. Short-term experiments excluded exchange reactions of deuterium from alkanes (Schimmelmann et al., 1999), however, thermally stressed kerogens are enriched in deuterium (Schoell, 1984). Therefore, we investigated the influence of maturity on the deltaD-values of alkanes and acyclic isoprenoids. In the Kupferschiefer horizon from the Polish Zechstein Basin thermal maturity of organic matter is correlated to burial depth yielding a natural long-term exchange experiment. The deltaD-values of extracted hydrocarbons linearly correlated with thermal maturity. These results enable the correction of deltaD values from biomarkers with known maturity and therefore expanding palaeoclimatic reconstructions using deltaD values to the geological past. References: SAUER, P.E., EGLINTON, T.I., HAYES, J.M., SCHIMMELMANN, A. &SESSIONS, A.L. (2001) Compound specific D/H ratios of lipid biomarkers from sediments as a proxy for environmental and climatic conditions. Geochimica et Cosmochimica Acta, 65(2), 213-222. SCHIMMELMANN, A., LEWAN, M.D. &WINTSCH, R.P. (1999) D/H isotope ratios of kerogen, bitumen, oil, and water in hydrous pyrolysis of source rocks containing kerogen types I, II, IIS, and III. Geochimica et Cosmochimica Acta, 63(22), 3751-3766. SCHOELL, M. (1984) Wasserstoff- und Kohlenstoffisotope in organischen Substanzen, Erdölen und Erdgasen. Schweitzerbart'sche Verlagsbuchhandlung, Stuttgart. Reihe D (67), 161pp.

  3. Evaluation of prompt neutron spectra for minor actinide nuclei

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1997-03-01

    Measurement data on fission prompt neutron spectra of minor actinide (MA) is much little, and its accuracy is also unsufficient. Therefore, conventional evaluation value of fission spectra of MA was assumed for its nuclear temperature by using a method of determining from its systemicity owing to assumption of the Maxwell type distribution, but it can be said that this method consider fully to features of MA isotopes. In this paper, some evaluation calculation results are shown by adopting an evaluation method developed by authors and based on modified Madland Nix model and are conducted by concept of physical properties on target nuclei. As a result, by adopting the level density parameter of fission fragments, the inverse process cross section, the fission product yield distribution and the total release energy, effect of inverse process cross section, mass distribution of fission product, calculation results of Cm isotope and systemicity of fission spectra of actinide isotope were investigated. (G.K.)

  4. Using trace element content and lead isotopic composition to assess sources of PM in Tijuana, Mexico

    Salcedo, D.; Castro, T.; Bernal, J. P.; Almanza-Veloz, V.; Zavala, M.; González-Castillo, E.; Saavedra, M. I.; Perez-Arvízu, O.; Díaz-Trujillo, G. C.; Molina, L. T.

    2016-05-01

    PM2.5 samples were collected at two urban sites (Parque Morelos (PQM) and CECyTE (CEC)) in Tijuana during the Cal-Mex campaign from May 24 to June 5, 2010. Concentration of trace elements (Mg, Al, Ti, V, Mn, Fe, Co, Ni, Zn, Cu, Ga, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Ba, La, Ce, and Pb), and Pb isotopic composition were determined in order to study the sources of PM impacting each site. Other chemical analysis (gravimetric, elemental and organic carbon (EC/OC), and polycyclic aromatic hydrocarbons (PAHs)), were also performed. Finally, back-trajectories were calculated to facilitate the interpretation of the chemical data. Trace elements results show that CEC is a receptor site affected by mixed regional sources: sea salt, mineral, urban, and industrial. On the other hand, PQM seems to be impacted mainly by local sources. In particular, Pb at CEC is of anthropogenic, as well as crustal origin. This conclusion is supported by the lead isotopic composition, whose values are consistent with a combination of lead extracted from US mines, and lead from bedrocks in the Mexican Sierras. Some of the time variability observed can be explained using the back-trajectories.

  5. Recovering actinide values

    Actinide values are recovered from sodium carbonate scrub waste solutions containing these and other values along with organic compounds resulting from the radiolytic and hydrolytic degradation of neutral organophosphorus extractants such as tri-n butyl phosphate (TBP) and dihexyl-N, N-diethyl carbamylmethylene phosphonate (DHDECMP) which have been used in the reprocessing of irradiated nuclear reactor fuels. The scrub waste solution is made acidic with mineral acid, to form a feed solution which is then contacted with a water-immiscible, highly polar organic extractant which selectively extracts the degradation products from the feed solution. The feed solution can then be processed to recover the actinides for storage or recycled back into the high-level waste process stream. The extractant can be recycled after stripping the degradation products with a neutral sodium carbonate solution. (author)

  6. Environmental forcing does not induce diel or synoptic variation in carbon isotope content of forest soil respiration

    D. R. Bowling

    2015-04-01

    Full Text Available Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C of CO2 produced by respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation. We used an extensive suite of measurements to examine soil respiration over two months in a subalpine forest in Colorado, USA (the Niwot Ridge AmeriFlux forest. Observations included automated measurements of CO2 and δ13C of CO2 in the soil efflux, the soil gas profile, and forest air. There was strong diel variability in soil efflux, but no diel change in the δ13C of the soil efflux (δR or the CO2 produced by biological activity in the soil (δJ. Following rain, soil efflux increased significantly, but δR and δJ did not change. Temporal variation in the δ13C of the soil efflux was unrelated to measured environmental variables. Measurements of the δ13C of the soil efflux with chambers agreed closely with independent observations of the isotopic composition of soil CO2 production derived from soil gas well measurements. Deeper in the soil profile and at the soil surface, results confirmed established theory regarding diffusive soil gas transport and isotopic fractionation. Deviation from best-fit diffusion model results at the shallower depths illuminated a pump-induced ventilation artifact that should be anticipated and avoided in future studies. There was no evidence of natural pressure-induced ventilation of the deep soil. However, higher variability of δ13C of the soil efflux relative to δ13C of production derived from soil profile measurements was likely caused by transient pressure-induced transport with small horizontal length scales.

  7. Environmental forcing does not induce diel or synoptic variation in carbon isotope content of forest soil respiration

    Bowling, D. R.; Egan, J. E.; Hall, S. J.; Risk, D. A.

    2015-04-01

    Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C) of CO2 produced by respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature) and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation). We used an extensive suite of measurements to examine soil respiration over two months in a subalpine forest in Colorado, USA (the Niwot Ridge AmeriFlux forest). Observations included automated measurements of CO2 and δ13C of CO2 in the soil efflux, the soil gas profile, and forest air. There was strong diel variability in soil efflux, but no diel change in the δ13C of the soil efflux (δR) or the CO2 produced by biological activity in the soil (δJ). Following rain, soil efflux increased significantly, but δR and δJ did not change. Temporal variation in the δ13C of the soil efflux was unrelated to measured environmental variables. Measurements of the δ13C of the soil efflux with chambers agreed closely with independent observations of the isotopic composition of soil CO2 production derived from soil gas well measurements. Deeper in the soil profile and at the soil surface, results confirmed established theory regarding diffusive soil gas transport and isotopic fractionation. Deviation from best-fit diffusion model results at the shallower depths illuminated a pump-induced ventilation artifact that should be anticipated and avoided in future studies. There was no evidence of natural pressure-induced ventilation of the deep soil. However, higher variability of δ13C of the soil efflux relative to δ13C of production derived from soil profile measurements was likely caused by transient pressure-induced transport with small horizontal length scales.

  8. Environmental forcing does not induce diel or synoptic variation in the carbon isotope content of forest soil respiration

    Bowling, D. R.; Egan, J. E.; Hall, S. J.; Risk, D. A.

    2015-08-01

    Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C) of CO2 produced by the respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature) and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation). We used an extensive suite of measurements to examine soil respiration over 2 months in a subalpine forest in Colorado, USA (the Niwot Ridge AmeriFlux forest). Observations included automated measurements of CO2 and δ13C of CO2 in the soil efflux, the soil gas profile, and forest air. There was strong diel variability in soil efflux but no diel change in the δ13C of the soil efflux (δR) or the CO2 produced by biological activity in the soil (δJ). Following rain, soil efflux increased significantly, but δR and δJ did not change. Temporal variation in the δ13C of the soil efflux was unrelated to measured environmental variables, and we failed to find an explanation for this unexpected result. Measurements of the δ13C of the soil efflux with chambers agreed closely with independent observations of the isotopic composition of soil CO2 production derived from soil gas well measurements. Deeper in the soil profile and at the soil surface, results confirmed established theory regarding diffusive soil gas transport and isotopic fractionation. Deviation from best-fit diffusion model results at the shallower depths illuminated a pump-induced ventilation artifact that should be anticipated and avoided in future studies. There was no evidence of natural pressure-induced ventilation of the deep soil. However, higher variability in δ13C of the soil efflux relative to δ13C of production derived from soil profile measurements was likely caused by transient pressure-induced transport with small horizontal length scales.

  9. Production and measurement of minor actinides in the commercial fuel cycle

    Stanbro, W.D. [comp.

    1997-03-01

    The minor actinide elements, particularly neptunium and americium, are produced as a normal byproduct of the operation of thermal power reactors. Because of the existence of long-lived isotopes of these elements, they constitute the major sources of the residual radiation in spent fuel or in wastes resulting from reprocessing. This has led to examinations by some countries of the possibility of separating the minor actinides from waste products. The papers found in this report address the production of minor actinides in common thermal power reactors as well as approaches to measure these materials in various media. The first paper in this volume, {open_quotes}Production of Minor Actinides in the Commercial Fuel Cycle,{close_quotes} uses calculations with the ORIGEN2 reactor and decay code to estimate the amounts of minor actinides in spent fuel and separated plutonium as a function of reactor irradiation and the time after discharge. The second paper, {open_quotes}Destructive Assay of Minor Actinides,{close_quotes} describes a number of promising approaches for the chemical analysis of minor actinides in the various forms in which they are found at reprocessing plants. The next paper, {open_quotes}Hybrid KED/XRF Measurement of Minor Actinides in Reprocessing Plants,{close_quotes} uses the results of a simulation model to examine the possible applications of the hybrid KED/XRF instrument to the determination of minor actinides in some of the solutions found in reprocessing plants. In {open_quotes}Calorimetric Assay of Minor Actinides,{close_quotes} the authors show some possible extensions of this powerful technique beyond the normal plutonium assays to include the minor actinides. Finally, the last paper in this volume, {open_quotes}Environment Measurements of Transuranic Nuclides,{close_quotes} discusses what is known about the levels of the minor actinides in the environment and ways to analyze for these materials in environmental matrices.

  10. Activation analysis of pit-coal ash content with the use of isotopic fast neutron source

    The neutron activation techniques of coal ash determination are briefly reviewed and a new version of activation analysis using fast neutrons from 239Pu-Be source and basing on the reactions 28Si(n,p)28Al and 27Al(n,p)27Mg is proposed. 72 samples of pit-coals with ash content ranging from 3 to 40% were measured. The linear calibration function between ash content and both, 1.78 MeV and 0.84 MeV, γ-ray counts was obtained. The precision (0.94% ash for 17% ash content) and accuracy (1.4%ash for the whole range) were evaluated. Comparison of the results with those of fluorescent-scattering methods is made. (author)

  11. Alternatives to isotope ratio mass spectrometry for the measurement of deuterium content of body water

    The measurement of breast milk intake using the isotope dilution techniques is now well established. The methodology involves the administration of a bolus of tracer followed by observation of the kinetics of its passage though the system. For example in the popular 'dose to the mother' method a dose of labeled water is administered to the mother, and over the following days samples of body fluids are taken and the concentration of tracer determined in order to establish the rate of loss of tracer from her body. Likewise samples are taken from the breast fed infant in order to determine the rates of tracer intake and subsequent loss. Deuterium is the tracer of choice for these experiments since it is non-radioactive, and therefore suitable for use in these vulnerable subject groups, and also because of its relative cheapness. Conventionally isotope ratio mass spectrometry (IRMS) has been used for the determination of the amount of deuterium in the body fluids. However this methodology is expensive (an instrument might typically cost US$ 150,000), and it requires a considerable amount of dedicated technical expertise for its operation. Consequently such instrumentation is not widely available, and this has limited the number and scope of studies using this technique. Recently there have been reports of possible alternative technologies for the determination of deuterium in body water which appear attractive because of the wider general availability of the equipment required. It is the purpose of this report to assess these reported methods for their suitability for breast milk intake measurements

  12. Actinides: why are they important biologically

    The following topics are discussed: actinide elements in energy systems; biological hazards of the actinides; radiation protection standards; and purposes of actinide biological research with regard to toxicity, metabolism, and therapeutic regimens

  13. Photoelectron spectra of actinide compounds

    A brief overview of the application of photoelectron spectroscopy is presented for the study of actinide materials. Phenomenology as well as specific materials are discussed with illustrative examples

  14. Diet of harbor porpoises along the Dutch coast: A combined stable isotope and stomach contents approach

    Jansen, O.E.; Michel, L.; Lepoint, G.; Das, K.; Couperus, A.S.; Reijnders, P.J.H.

    2013-01-01

    High stranding frequency of porpoises, Phocoena phocoena, along the Dutch coast since 2006 has led to increased interest in the ecology of porpoises in the North Sea. Stranded porpoises were collected along the Dutch coast (2006–2008) and their diet was assessed through stomach content and stable is

  15. Certification measurement of the cadmium, copper and lead contents in rice using isotope dilution inductively coupled plasma mass spectrometry

    This paper describes the certification of the Cd, Cu and Pb amount contents in a rice material, that were used as reference values for round 19 of the international measurement evaluation programme (IMEP). The protocol developed in this study was based on isotope dilution associated to inductively coupled plasma mass spectrometry (ID-ICP-MS). A multiple spiking approach was applied to reduce significantly the number of analytical steps. For the decomposition of the sample, three different microwave assisted digestion procedures were tested and compared. The use of hydrofluoric acid was found necessary to ensure full solubilisation and complete isotopic equilibration. Estimation of the combined uncertainty attached to the measurement results was performed according to the ISO guidelines. Contributions from the correction for moisture content, sample homogeneity, procedural blank, spike impurities, spectral interferences, instrumental background and dead-time effects were evaluated. SI-traceable values with less than 2% combined uncertainty (k = 2) were obtained for Cd, Cu and Pb, respectively, (14.39 ± 0.21) x 10-6 mol kg-1, (44.31 ± 0.42) x 10-6 mol kg-1 and (2.034 ± 0.034) x 10-6 mol kg-1. The rice powder was observed to be highly hygroscopic and a second series of isotope dilution mass spectrometry measurements was carried out on samples in equilibrium with the ambient moisture conditions ('saturated' samples). The Comite Consultatif pour la Quantite de Matiere (CCQM) requested this approach for the participation to the key comparison 24 on the same rice test material. The excellent agreement for Cd between the IMEP-19 reference value, the value submitted by the institute for reference materials and measurements (IRMM) to CCQM-K24 and the corresponding reference value obtained as the arithmetic mean from the results of the 11 participating National Measurement Institutes (less than 0.27% difference) further validated this work. Eventually, this series of

  16. Actinides in irradiated graphite of RBMK-1500 reactor

    Highlights: • Activation of actinides in the graphite of the RBMK-1500 reactor was analyzed. • Numerical modeling using SCALE 6.1 and MCNPX was used for actinide calculation. • Measurements of the irradiated graphite sample were used for model validation. • Results are important for further decommissioning process of the RBMK type reactors. - Abstract: The activation of graphite in the nuclear power plants is the problem of high importance related with later graphite reprocessing or disposal. The activation of actinide impurities in graphite due to their toxicity determines a particular long term risk to waste management. In this work the activation of actinides in the graphite constructions of the RBMK-1500 reactor is determined by nuclear spectrometry measurements of the irradiated graphite sample from the Ignalina NPP Unit I and by means of numerical modeling using two independent codes SCALE 6.1 (using TRITON-VI sequence) and MCNPX (v2.7 with CINDER). Both models take into account the 3D RBMK-1500 reactor core fragment with explicit graphite construction including a stack and a sleeve but with a different simplification level concerning surrounding graphite and construction of control roads. The verification of the model has been performed by comparing calculated and measured isotope ratios of actinides. Also good prediction capabilities of the actinide activation in the irradiated graphite have been found for both calculation approaches. The initial U impurity concentration in the graphite model has been adjusted taking into account the experimental results. The specific activities of actinides in the irradiated RBMK-1500 graphite constructions have been obtained and differences between numerical simulation results, different structural parts (sleeve and stack) as well as comparison with previous results (Ancius et al., 2005) have been discussed. The obtained results are important for further decommissioning process of the Ignalina NPP and other RBMK

  17. Carbon isotopic composition, nitrogen content and inclusion composition of diamonds from the Roberts Victor kimberlite, South Africa: Evidence for 13C depletion in the mantle

    The mean 13C-content of diamonds containing peridotitic minerals does not differ significantly from those containing sulfides. Diamonds containing eclogitic minerals can be subdivided into two groups based on their carbon isotopic composition: Group-A, and Group-B. The clinopyroxenes occluded by the Group-A diamonds are depleted in SiO2, MgO, and CaO and significantly enriched in Al2O3, FeO, and MnO compared to clinopyroxenes occluded by Group-B diamonds. Carbon in two graphite-diamond eclogites has a mean isotopic composition of -5.31%; in both samples graphite shows a slight enrichment in 13C compared to the coexisting diamond. There is no difference in the C isotopic composition between Type I and Type II diamonds for sulfide and peridotitic minerals occluding diamonds. All Type II diamonds containing eclogitic minerals belong to Group-A. No correlation between N content and C isotopic composition could be established, although a large range in both variables is observed for the sample suite. The composition of eclogitic minerals included in diamonds of low 13C-content differs from that of eclogite xenoliths characterized by 18O-depletions, which have been related to subduction processes. Hence the data available do not suggest a common cause for the depletion of the heavy isotopes of the two elements. The chemical and isotopic characteristics of the suite of diamond samples reflect different mantle environments. Diamonds depleted in 13C(13C = -15 to -16 per mille) come from a region at greater depth than those of 13C contents of -5 to -6 per mille. The source region of the former is characterized by higher Fe, Mn, Al, and lower Mg, Ca, Si, and N contents than that of the latter. (author)

  18. Simulation of fuel cycles with minor actinide management using a fast burnup calculation tool

    The paper presents a fast and flexible burnup model for fuel cycle simulations which is based on the description of the one-group cross-sections as analytic functions of the isotopic composition. This was accomplished by multi-dimensional regression based on the results of numerous core calculations. The developed model is able to determine the spent fuel composition in reasonable CPU time, and was integrated into a simplified fuel cycle model containing Gas Cooled Fast Reactors (GFR) and conventional light water reactors (LWRs). The fuel cycle simulations revealed an advantageous effect of increased minor actinide content in the GFR core on the fuel utilization parameters. In order to explore the processes that lay behind this effect the neutronics balance of the GFR was investigated in equilibrium cycle conditions. (author)

  19. Actinides record, power calculations and activity for present isotopes in the spent fuel of a BWR; Historial de actinidos y calculos de potencia y actividad para isotopos presentes en el combustible gastado de un BWR

    Enriquez C, P.; Ramirez S, J. R.; Lucatero, M. A., E-mail: pastor.enriquez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    The administration of spent fuel is one of the more important stages of the nuclear fuel cycle, and this has become a problem of supreme importance in countries that possess nuclear reactors. Due to this in this work, the study on the actinides record and present fission products to the discharge of the irradiated fuel in a light water reactor type BWR is shown, to quantify the power and activity that emit to the discharge and during the cooling time. The analysis was realized on a fuel assembly type 10 x 10 with an enrichment average of 3.69 wt % in U-235 and the assembly simulation assumes four cycles of operation of 18 months each one and presents an exposition of 47 G Wd/Tm to the discharge. The module OrigenArp of the Scale 6 code is the computation tool used for the assembly simulation and to obtain the results on the actinides record presents to the fuel discharge. The study covers the following points: a) Obtaining of the plutonium vector used in the fuel production of mixed oxides, and b) Power calculation and activity for present actinides to the discharge. The results presented in this work, correspond at the same time immediate of discharge (0 years) and to a cooling stage in the irradiated fuel pool (5 years). (Author)

  20. Advanced concepts for gamma-ray isotopic analysis and instrumentation

    The Safeguards Technology Program at the Lawrence Livermore National Laboratory is developing actinide isotopic analysis technologies in response to needs that address issues of flexibility of analysis, robustness of analysis, ease-of-use, automation and portability. Recent developments such as the Intelligent Actinide Analysis System (IAAS), begin to address these issues. We are continuing to develop enhancements on this and other instruments that improve ease-of-use, automation and portability. Requests to analyze samples with unusual isotopics, contamination, or containers have made us aware of the need for more flexible and robust analysis. We have modified the MGA program to extend its plutonium isotopic analysis capability to samples with greater 241Am content or U isotopics. We are looking at methods for dealing with tantalum or lead contamination and contamination with high-energy gamma emitters, such as 233U. We are looking at ways to allow the program to use additional information about the sample to further extend the domain of analyzable samples. These unusual analyses will come from the domain of samples that need to be measured because of complex reconfiguration or environmental cleanup

  1. Advanced concepts for gamma ray isotopic analysis and instrumentation

    Buckley, W. M.; Carlson, J. B.

    1994-07-01

    The Safeguards Technology Program at the Lawrence Livermore National Laboratory is developing actinide isotopic analysis technologies in response to needs that address issues of flexibility of analysis, robustness of analysis, ease-of-use, automation and portability. Recent developments such as the Intelligent Actinide Analysis System (IAAS), begin to address these issues. We are continuing to develop enhancements on this and other instruments that improve ease-of-use, automation and portability. Requests to analyze samples with unusual isotopics, contamination, or containers have made us aware of the need for more flexible and robust analysis. We have modified the MGA program to extend its plutonium isotopic analysis capability to samples with greater Am-241 content or U isotopics. We are looking at methods for dealing with tantalum or lead contamination and contamination with high-energy gamma emitters, such as U-233. We are looking at ways to allow the program to use additional information about the sample to further extend the domain of analyzable samples. These unusual analyses will come from the domain of samples that need to be measured because of complex reconfiguration or environmental cleanup.

  2. Advanced concepts for gamma-ray isotopic analysis and instrumentation

    Buckley, W.M.; Carlson, J.B.

    1994-07-01

    The Safeguards Technology Program at the Lawrence Livermore National Laboratory is developing actinide isotopic analysis technologies in response to needs that address issues of flexibility of analysis, robustness of analysis, ease-of-use, automation and portability. Recent developments such as the Intelligent Actinide Analysis System (IAAS), begin to address these issues. We are continuing to develop enhancements on this and other instruments that improve ease-of-use, automation and portability. Requests to analyze samples with unusual isotopics, contamination, or containers have made us aware of the need for more flexible and robust analysis. We have modified the MGA program to extend its plutonium isotopic analysis capability to samples with greater {sup 241}Am content or U isotopics. We are looking at methods for dealing with tantalum or lead contamination and contamination with high-energy gamma emitters, such as {sup 233}U. We are looking at ways to allow the program to use additional information about the sample to further extend the domain of analyzable samples. These unusual analyses will come from the domain of samples that need to be measured because of complex reconfiguration or environmental cleanup.

  3. Optical techniques for actinide research

    In recent years, substantial gains have been made in the development of spectroscopic techniques for electronic properties studies. These techniques have seen relatively small, but growing, application in the field of actinide research. Photoemission spectroscopies, reflectivity and absorption studies, and x-ray techniques will be discussed and illustrative examples of studies on actinide materials will be presented

  4. Application of hydrochemical and tritium content measurements as well as stable isotope ratios for assessment of strip mine impact on environment

    The hydrochemical measurements, tritium content and stable isotope ration 34S/32S and 18O/16O have been used for Belchatow strip mine impact assessment on environmental waters. The sources of pollution can be localized on this base. (author)

  5. An overview of noble gas (He, Ne, Ar, Xe) contents and isotope signals in terrestrial diamond

    Basu, S.; Jones, A. P.; Verchovsky, A. B.; Kelley, S. P.; Stuart, F. M.

    2013-11-01

    high 21Ne/22Ne and 131,134,136Xe/132Xe ratios. In many diamonds, variations in both concentration and isotopic composition within samples from the same geographical location require complex diamond growth. For example, coated stones of Zaire trap noble gases from multiple sources and different generations of diamond growth. Thus noble gas studies have the potential to record major processes during the complex growth histories of natural diamond and also to provide valuable information about the sub-continental mantle. Noble gas signatures may be affected by diffusive losses, notably in some framesites.

  6. Determination of Mercury Content in a Shallow Firn Core from Summit, Greenland by Isotope Dilution Inductively Coupled Plasma Mass Spectrometry

    Mann, Jacqueline L.; Long, Stephen E.; Shuman, Christopher A.; Kelly, W. Robert

    2003-01-01

    The total mercury Hg content was determined in 6 cm sections of a near-surface 7 m firn core and in surrounding surface snow from Summit, Greenland (elevation: 3238 m, 72.58 N, 38.53 W) in May 2001 by isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS). The focus of this research was to evaluate the capability of the ID-CV-ICPMS technique for measuring trace levels of Hg typical of polar snow and firn. Highly enriched Hg-201 isotopic spike is added to approximately 10 ml melted core and thoroughly mixed. The Hg(+2) in the sample is reduced on line with tin (II) chloride (SnCl2) and the elemental Hg (Hg(0)) vapor pre-concentrated on to gold gauze using a commercial amalgam system. The Hg is then thermally desorbed and introduced into a quadrupole ICP-MS. The blank corrected Hg concentrations determined for all samples ranged from 0.25 ng/L to 1.74 ng/L (ppt) (average 0.59 ng/L plus or minus 0.28 ng/L) and fall within the range of those previously determined by Boutron et al., 1998 (less than or equal to 0.05 ng/L to 2.0 ng/L) for the Summit site. The average blank value was 0.19 ng/L plus or minus 0.045 ng/L (n=6). The Hg values specifically for the firn core range from 0.25 ng/L to 0.87 ng/L (average 0.51 ng/L plus or minus 0.13 ng/L) and show both values declining with time and larger variability in concentration in the top 1.8 m.

  7. The isotopic composition and content of sulphur in soils of Kansk-Achinsk fuel power generation complex

    In the 1970s the first phase of a large coal-burning power complex was brought into operation in the Kansk-Achinsk region of the Soviet Union. The target consumption for this complex is 50 x 106 tonnes yr-1 and most of this is supplied from local open-pit mines. The emission of SO2 from this plant caused concern as to its impact on the local environment and prompted a study of the sulphurous depositions. Monitoring the areal extent and distribution of the deposited S and its fate in the environment can be a mammoth task involving continual measurement of many biological and physical factors including atmospheric concentrations, wind speed, emission rates, and forms of S in soil, plants, and animals. A possible alternative for evaluating the amount, distribution, and fate of the emitted S in the ecosystem is stable sulphur isotope analyses since different coals and SO2 from their combustion often have δ34S values differing from those of soils and plants in the region. The study reported here was initiated to see if the δ34S values for emissions differed significantly from the natural environment. Assuming that the difference was sufficient, a second objective was to document changes that have occurred in the sulphur isotope compositions of the environmental receptors over time. Soil samples from 23 sites were collected and analysed for S content and δ34S values. Coal, cinder and ash collected from furnaces and SO2 from the combustion products were similarly analysed. Figs and tabs

  8. The fission fragment yields at the photofission of actinide nuclei

    The fission fragment yields of isotopes 101Mo, 135I, 135mCs were measured at the photo-fission of actinide nuclei 232Th, 238U, 237Np. These fission fragments have some peculiarities in nuclear structure or in practical using. The measurements were performed on the microtron bremsstrahlung at the Flerov Laboratory of Nuclear Reactions, JINR, at the electron energy 22 MeV. The activation method with an HPGe detector was used in these measurements of the yields

  9. Variations of Microbial Communities and the Contents and Isotopic Compositions of Total Organic Carbon and Total Nitrogen in Soil Samples during Their Preservation

    TAO Qianye; LI Yumei; WANG Guo'an; QIAO Yuhui; LIU Tung-Sheng

    2009-01-01

    Semi-sealed preservation of soil samples at difierent moisture of 4%and 23%,respectively, was simulated to observe the variations of soil microbiaI communities and determine the contents and isotopic compositions of the total organic carbon and total nitrogen on the 7th and 30th day, respectively.The results show that during preservation,the quantity of microbial communities tended to increase first and then decrease,with a wider variation range at higher moisture(23%).At the moisture content of 23%,the microbial communities became more active on the 7th day.but less after 30 days,and their activity Was stable with little fluctuation at the moisture content of 4%.However. there were no significant changes in the contents and isotopic compositions of the total organic carbon and total nitrogen.During preservation.the responses of soil microbes to the environment are more sensitive to changes in the total nitrogen and organic carbon contents.It is thus suggested that the variations of microbial communities have not exerted remarkable impacts on the isotope compositions of the total nitrogen and total organic carbon.

  10. Radioecology of the actinide elements

    Research progress is reported in sections entitled: scope of studies supported by the Department of Energy; oxidation state diagrams are a potential tool for studying the redox chemistry of Pu in natural waters; studies are initiated to investigate the effect of pH and organic matter on the distribution coefficients of Cm with natural sediments; the relative distributions of resuspended and direct deposited Pu in a corn canopy are quantified; the retention of Pu surface contamination by corn plants is being studied; Pu concentrations in tobacco are being determined; concentrations of Pu per unit mass and per unit surface area are compared for subterranean crops; models of Pu behavior in agricultural crops are being validated; distribution of aerially released Pu in loblolly pine plantations is independent of deposition rate; investigation of the effects of chelate and redox potential of the uptake of Pu and Cm by rice is underway; studies of Cm cycling in a floodplain forest have been initiated; the effects of unusually large Pu deposition onto a wheat ecosystem are being studied using computer simulations; long-term kinetic models of Pu behavior in plant-soil systems are being developed; scope of studies supported by the Nuclear Regulatory Commission; growth form of broadleaf crop may affect Pu contents; root uptake of Pu and Cm measured for rice root uptake of Pu and Cm measured for rice; long-term actinide uptake study is continuing at SREL; and uranium cycling in major southeastern agricultural crops being studied

  11. Concentration of actinides in the food chain

    Considerable concern is now being expressed over the discharge of actinides into the environment. This report presents a brief review of the chemistry of the actinides and examines the evidence for interaction of the actinides with some naturally-occurring chelating agents and other factors which might stimulate actinide concentration in the food chain of man. This report also reviews the evidence for concentration of actinides in plants and for uptake through the gastrointestinal tract. (author)

  12. Reactor Physics Studies of Reduced-Tantaulum-Content Control and Safety Elements for the High Flux Isotope Reactor

    Some of the unirradiated High Flux Isotope Reactor (HFIR) control elements discharged during the late 1990s were observed to have cladding damage--local swelling or blistering. The cladding damage was limited to the tantalum/europium interface of the element and is thought to result from interaction of hydrogen and europium to form a compound of lower density than europium oxide, thus leading to a ''blistering'' of the control plate cladding. Reducing the tantalum loading in the control plates should help preclude this phenomena. The impact of the change to the control plates on the operation of the reactor was assessed. Regarding nominal, steady-state reactor operation, the impact of the change in the power distribution in the core due to reduced tantalum content was calculated and found to be insignificant. The magnitude and impact of the change in differential control element worth was calculated, and the differential worths of reduced tantalum elements vs the current elements from equivalent-burnup critical configurations were determined to be unchanged within the accuracy of the computational method and relevant experimental measurements. The location of the critical control elements symmetric positions for reduced tantalum elements was found to be 1/3 in. less withdrawn relative to existing control elements regardless of the value of fuel cycle burnup (time in the fuel cycle). The magnitude and impact of the change in the shutdown margin (integral rod worth) was assessed and found to be unchanged. Differential safety element worth values for the reduced-tantalum-content elements were calculated for postulated accident conditions and were found to be greater than values currently assumed in HFIR safety analyses

  13. Actinide management with commercial fast reactors

    Ohki, Shigeo

    2015-12-01

    The capability of plutonium-breeding and minor-actinide (MA) transmutation in the Japanese commercial sodium-cooled fast reactor offers one of practical solutions for obtaining sustainable energy resources as well as reducing radioactive toxicity and inventory. The reference core design meets the requirement of flexible breeding ratio from 1.03 to 1.2. The MA transmutation amount has been evaluated as 50-100 kg/GWey if the MA content in fresh fuel is 3-5 wt%, where about 30-40% of initial MA can be transmuted in the discharged fuel.

  14. Actinide management with commercial fast reactors

    The capability of plutonium-breeding and minor-actinide (MA) transmutation in the Japanese commercial sodium-cooled fast reactor offers one of practical solutions for obtaining sustainable energy resources as well as reducing radioactive toxicity and inventory. The reference core design meets the requirement of flexible breeding ratio from 1.03 to 1.2. The MA transmutation amount has been evaluated as 50-100 kg/GWey if the MA content in fresh fuel is 3-5 wt%, where about 30-40% of initial MA can be transmuted in the discharged fuel

  15. Actinide management with commercial fast reactors

    Ohki, Shigeo [Japan Atomic Energy Agency, 4002, Narita-cho, O-arai-machi, Higashi-Ibaraki-gun, Ibaraki 311-1393 (Japan)

    2015-12-31

    The capability of plutonium-breeding and minor-actinide (MA) transmutation in the Japanese commercial sodium-cooled fast reactor offers one of practical solutions for obtaining sustainable energy resources as well as reducing radioactive toxicity and inventory. The reference core design meets the requirement of flexible breeding ratio from 1.03 to 1.2. The MA transmutation amount has been evaluated as 50-100 kg/GW{sub e}y if the MA content in fresh fuel is 3-5 wt%, where about 30-40% of initial MA can be transmuted in the discharged fuel.

  16. Inhaled actinides: some safety issues and some research problems

    The following topics are discussed: limited research funds; risk coefficients for inhaled particles; the hot particle hypothesis; the Gofman-Martell contention; critical tissues for inhaled actinides inhalation hazards associated with future nuclear fuel cycles; and approach to be used by the inhalation panel

  17. Changes in formation gas composition and isotope content as indicators of unsaturated-zone chemical reactions related to recharge events

    The constituent composition and carbon and oxygen isotopes for CO2 in unsaturated-zone gases have been utilized to provide an independent means of determining what chemical reactions occurred during an extended artificial recharge experiment on the High Plains of Texas. Gas samples were collected from a sample point at a depth of 16 metres beneath a waterspreading basin to see what effect recharging water had on the unsaturated-zone atmosphere. Two different systems, one open and one closed, were sampled during this study. The 13C, 18O, Psub(CO2), and N/Ar data for gas collected during a 1975 experiment show the influence of unsaturated-zone gases being displaced by recharging waters, the trend towards equilibration with dissolved atmospheric gases as the sampling point is submerged by rising waters, the onset of a reducing environment and, following the termination of recharge, the slow recovery of the gas composition to pre-recharge conditions. The 13C content of the CO2 in the gases varied from -18.06% for the pre-recharge formation gas, to -10.01% for gases approaching equilibrium with dissolved atmospheric gases, to -38.01% for a CO2 produced from methane generated in a reducing evironment. The log Psub(CO2) for the above samples varied from -2.10 to -3.02 to -4.18 atmospheres, respectively. Recovery to pre-recharge unsaturated-zone atmospheric conditions took many months following the termination of recharge. (author)

  18. Fission product and actinide data evaluations for ENDF/B--V

    Schenter, R.E.

    1978-05-01

    The planned content and performance of fission product and actinide nuclide evaluations for the ENDF/B-V collection of data are reviewed. Representative values of parameters for a few nuclides are shown. 10 figures, 5 tables. (RWR)

  19. Actinides and the environment

    The book combines in one volume the opinions of experts regarding the interaction of radionuclides with the environment and possible ways to immobilize and dispose of nuclear waste. The relevant areas span the spectrum from pure science, such as the fundamental physics and chemistry of the actinides, geology, environmental transport mechanisms, to engineering issues such as reactor operation and the design of nuclear waste repositories. The cross-fertilization between these various areas means that the material in the book will be accessible to seasoned scientists who may wish to obtain an overview of the current state of the art in the field of environmental remediation of radionuclides, as well as to beginning scientists embarking on a career in this field. refs

  20. Fusion-Fission Burner for Transuranic Actinides

    Choi, Chan

    2013-10-01

    The 14-MeV DT fusion neutron spectrum from mirror confinement fusion can provide a unique capability to transmute the transuranic isotopes from light water reactors (LWR). The transuranic (TRU) actinides, high-level radioactive wastes, from spent LWR fuel pose serious worldwide problem with long-term decay heat and radiotoxicity. However, ``transmuted'' TRU actinides can not only reduce the inventory of the TRU in the spent fuel repository but also generate additional energy. Typical commercial LWR fuel assemblies for BWR (boiling water reactor) and PWR (pressurized water reactor) measure its assembly lengths with 4.470 m and 4.059 m, respectively, while its corresponding fuel rod lengths are 4.064 m and 3.851 m. Mirror-based fusion reactor has inherently simple geometry for transmutation blanket with steady-state reactor operation. Recent development of gas-dynamic mirror configuration has additional attractive feature with reduced size in central plasma chamber, thus providing a unique capability for incorporating the spent fuel assemblies into transmutation blanket designs. The system parameters for the gas-dynamic mirror-based hybrid burner will be discussed.

  1. Content

    Keiding, Tina Bering

    Aim, content and methods are fundamental categories of both theoretical and practical general didactics. A quick glance in recent pedagogical literature on higher education, however, reveals a strong preoccupation with methods, i.e. how teaching should be organized socially (Biggs & Tang, 2007; R...... strategy is theoretically based on systems theory as formulated by Niklas Luhmann (Luhmann, 1995; 2002) and on own work, where. Luhmann’s general ideas and concepts of the educational system are transposed into a didactical framework (Keiding, 2005,2007,2008).......Aim, content and methods are fundamental categories of both theoretical and practical general didactics. A quick glance in recent pedagogical literature on higher education, however, reveals a strong preoccupation with methods, i.e. how teaching should be organized socially (Biggs & Tang, 2007......, is subordinating content to methods as seen in modern didactics, hereby transforming content to a medium for achievement of learning-to-learn skills rather than something valuable in its own right. At the level of general didactics quite few attempts have been made to formulate criteria and...

  2. In vivo measurement of actinides in the human lung

    The problems associated with the in vivo detection and measurement of actinides in the human lung are discussed together with various measurement systems currently in use. In particular, the methods and calibration procedures employed at the Lawrence Livermore Laboratory, namely, the use of twin Phoswich detectors and a new, more realistic, tissue-equivalent phantom, are described. Methods for the measurement of chest-wall thickness, fat content, and normal human background counts are also discussed. Detection-efficiency values and minimum detectable activity estimates are given for three common actinides, 238Pu, 239Pu, and 241Am

  3. Environmental research on actinide elements

    The papers synthesize the results of research sponsored by DOE's Office of Health and Environmental Research on the behavior of transuranic and actinide elements in the environment. Separate abstracts have been prepared for the 21 individual papers

  4. Actinides, accelerators and erosion

    Fifield L.K.

    2012-10-01

    Full Text Available Fallout isotopes can be used as artificial tracers of soil erosion and sediment accumulation. The most commonly used isotope to date has been 137Cs. Concentrations of 137Cs are, however, significantly lower in the Southern Hemisphere, and furthermore have now declined to 35% of original values due to radioactive decay. As a consequence the future utility of 137Cs is limited in Australia, with many erosion applications becoming untenable within the next 20 years, and there is a need to replace it with another tracer. Plutonium could fill this role, and has the advantages that there were six times as many atoms of Pu as of 137Cs in fallout, and any loss to decay has been negligible due to the long half-lives of the plutonium isotopes. Uranium-236 is another long-lived fallout isotope with significant potential for exploitation as a tracer of soil and sediment movement. Uranium is expected to be more mobile in soils than plutonium (or caesium, and hence the 236U/Pu ratio will vary with soil depth, and so could provide an independent measure of the amount of soil loss. In this paper we discuss accelerator based ultra-sensitive measurements of plutonium and 236U isotopes and their advantages over 137Cs as tracers of soil erosion and sediment movement.

  5. Properties of minor actinide nitrides

    The present status of the research on properties of minor actinide nitrides for the development of an advanced nuclear fuel cycle based on nitride fuel and pyrochemical reprocessing is described. Some thermal stabilities of Am-based nitrides such as AmN and (Am, Zr)N were mainly investigated. Stabilization effect of ZrN was cleary confirmed for the vaporization and hydrolytic behaviors. New experimental equipments for measuring thermal properties of minor actinide nitrides were also introduced. (author)

  6. The advanced liquid metal reactor actinide recycle system

    The current U.S. National Energy Strategy includes four key goals for nuclear policy: enhance safety and design standards, reduce economic risk, reduce regulatory risk, and establish an effective high-level nuclear waste program. The U.S. Department of Energy's Advanced Liquid Metal Reactor Actinide Recycle System is consistent with these objectives. The system has the ability to fulfill multiple missions with the same basic design concept. In addition to providing an option for long-term energy security, the system can be effectively utilized for recycling of actinides in light water reactor (LWR) spent fuel, provide waste management flexibility, including the reduction in the waste quantity and storage time and utilization of the available energy potential of LWR spent fuel. The actinide recycle system is comprised of (1) a compact liquid metal (sodium) cooled reactor system with optimized passive safety characteristics, and (2) pyrometallurgical metal fuel cycle presently under development of Argonne National Laboratory. The waste reduction of LWR spent fuel is accomplished by transmutation or fissioning of the longer-lived transuranic isotopes to shorter-lived fission products in the reactor. In this presentation the economical and environmental incentive of the actinide recycle system is addressed and the status of development including licensing aspects is described. 3 refs., 1 tab., 6 figs

  7. Reducing the impact of used fuel by transmuting actinides in a CANDU reactor

    With world stockpiles of used nuclear fuel increasing, the need to address the long term utilization of this resource is being studied. Many of the transuranic (TRU) actinides in nuclear spent fuel produce decay heat for long durations, resulting in significant nuclear waste management challenges. These actinides can be transmuted to shorter-lived isotopes in CANDU reactors to reduce the decay heat period. Many of the design features of the CANDU reactor make it uniquely adaptable to actinide transmutation. The small, simple fuel bundle facilitates the fabrication and handling of active fuels. Online refueling allows precise management of core reactivity and separate insertion of the actinides and fuel bundles into the core. The high neutron economy of the CANDU reactor results in high TRU destruction to fissile-loading ratio. This paper provides a summary of actinide transmutation in CANDU reactors, including both recent and past activities. The transmutation schemes that are presented reflect several different partitioning schemes and include both homogeneous scenarios in which actinides are uniformly distributed in all fuel bundles in the reactor, as well as heterogeneous scenarios in which dedicated channels in the reactor are loaded with actinide targets and the rest of the reactor is loaded with fuel. (author)

  8. Critical evaluation of an isotope dilution ICP-MS method for the measurement of the Fe content in seawater

    It is well known that direct analysis of seawater by means of inductively coupled plasma mass spectrometry (ICP-MS) is hardly possible because of the salt load in the samples. Determination of the element content at ultra-trace level in open-ocean water requires a separation from the matrix associated to significant concentration factors. For iron, an isotope dilution (ID) ICP-MS method was proposed based on a multiple steps protocol, including a co-precipitation with magnesium hydroxide after ammonia loading and consecutive dissolution with hydrochloric acid. To be able to measure the iron content in the low pg g-1 range a correct assessment of the analytical procedural blank is of crucial importance. Not only this blank must be low, but also realistic (i.e. based on complete analytical sequence applied to real iron free seawater) and reproducible. This is particularly difficult considering the ubiquity of iron and the complexity of the seawater matrix and, despite years of experiments and publications, this remains a fundamental analytical challenge and a great source of complexity for the realisation of reliable profiles of dissolved iron data. The present study considers different approaches we developed to assess, in a realistic way, the procedural blank of the IDMS method proposed by Wu and Boyle. Our aim was to reproduce the full set of experimental steps involved in the determination of iron in seawater by IDMS at the nM level or below. Our results are evaluated in the light of those claimed by Wu and Boyle who use ∼4%-sample volume for their procedural blank determination. The results they present are rather convincing. However, downsizing by a factor of ∼25 the sample volume not only minimises sample-tube contact and labware contribution to the blank, but results as well in a different set of operations and manipulations. These changes in the analytical protocol can easily lead to non-realistic procedural blank values. This is illustrated in the

  9. Study of Factors Influencing Oxygen-18 Isotopic Contents of Dissolved Sulphate in the Shallow Groundwater In Karawang Area

    The study was conducted to investigate the factors influencing oxygen-18 isotopic contents of dissolved sulphate in shallow groundwater from Karawang area. The δ18O is a relative abundance of O-18 compared to O-16 in CO2 gas. CO2 gas was released from the equilibrium between water samples and CO2 gas, and from the reduction of sulphate samples with graphite. From this investigation, the δ18 O (H2O) values were in the range of -3.21 0/00 to 6.250/00 whereas the δ18O (SO42-) values were 9.64 0/00 to 20.72 0/00. The wide variation of δ18 O (SO42-) values might be result due to inhomogeneity of sulphate sources in groundwater where the groundwater sulphates were generally derived from the dissolution of marine evaporites rocks. The groundwaters and Citarum River near waters to Johar site showed lowering of δ18 O (SO42-) values. It might be related to the present of the traditional market in this location. The lowering of these values might be due to the increase of the sulphate reduction process caused by anaerobic bacteria growth in organic garbage deposition. Plotting between δ18O (SO42-) and δ18 O (H2O) exhibited that the oxygen contribution from H2O to form sulphate was less than 25%. This indicated that the shallow groundwater in Karawang is located in a non-saturated zone and had a biotic condition. (author)

  10. Near-IR laser-based spectrophotometer for comparative analysis of isotope content of CO{sub 2} in exhale air samples

    Stepanov, E V; Glushko, A N; Kasoev, S G; Koval' , A V; Lapshin, D A [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2011-12-31

    We present a laser spectrophotometer aimed at high-accuracy comparative analysis of content of {sup 12}CO{sub 2} and {sup 13}CO{sub 2} isotope modifications in the exhale air samples and based on a tunable near-IR diode laser (2.05 {mu}m). The two-channel optical scheme of the spectrophotometer and the special digital system for its control are described. An algorithm of spectral data processing aimed at determining the difference in the isotope composition of gas mixtures is proposed. A few spectral regions (near 4880 cm{sup -1}) are determined to be optimal for analysis of relative content of {sup 12}CO{sub 2} and {sup 13}CO{sub 2} in the exhale air. The use of the proposed spectrophotometer scheme and the developed algorithm makes the results of the analysis less susceptible to the influence of the interference in optical elements, to the absorption in the open atmosphere, to the slow drift of the laser pulse envelope, and to the offset of optical channels. The sensitivity of the comparative analysis of the isotope content of CO{sub 2} in exhale air samples, achieved using the proposed scheme, is estimated to be nearly 0.1 Per-Mille-Sign .

  11. Evaluation of the maximum content of a MOX-fueled pressurized water reactor versus isotopic composition with respect to the void coefficient

    The study is within the framework of the feasibility of 100% MOX recycling in a Pressurized Water Reactor. The objective is to determine the limit content of total plutonium in a MOX fuel with respect to the serious accident of core total draining, during which the reactivity effects must remain negative. Six isotopic vectors, from a very degraded plutonium to a plutonium with a high content of fissile nuclei, are studied. The very conservative result of 12% for the whole vectors allows to confirm, a posteriori, the dimensioning of recent factories intended for the production of MOX fuel. (author). 3 refs, 7 figs, 3 tabs

  12. CONTENTS

    2012-01-01

    The Development and Evolution of the Idea of the Mandate of Heaven in the Zhou Dynasty The changes in the idea of Mandate of Heaven during the Shang and Zhou dynasties are of great significance in the course of the development of traditional Chinese culture. The quickening and awakening of the humanistic spirit was not the entire content of the Zhou idea of Mandate of Heaven. In the process of annihilating the Shang dynasty and setting up their state, the Zhou propagated the idea of the Mandate of Heaven out of practical needs. Their idea of the Mandate of Heaven was not very different from that of the Shang. From the Western Zhou on, the Zhou idea of Mandate of Heaven by no means developed in a linear way along a rational track. The intermingling of rationality and irrationality and of awakening and non-awakening remained the overall state of the Zhou intellectual superstructure after their "spiritual awakening".

  13. THERMODYNAMICS OF THE ACTINIDES

    Cunningham, Burris B.

    1962-04-01

    Recent work on the thermodynamic properties of the transplutonium elements is presented and discussed in relation to trends in thermodynamic properties of the actinide series. Accurate values are given for room temperature lattice parameters of two crystallographic forms, (facecentred cubic) fcc and dhcp (double-hexagonal closepacked), of americium metal and for the coefficients of thermal expansion between 157 and 878 deg K (dhcp) and 295 to 633 deg K (fcc). The meiting point of the metal, and its magnetic susceptibility between 77 and 823 deg K are reported and the latter compared with theoretical values for the tripositive ion calculated from spectroscopic data. Similar data (crystallography, meiting point and magnetic susceptibility) are given for metallic curium. A value for the heat of formation of americium monoxide is reported in conjunction with crystallographic data on the monoxide and mononitride. A revision is made in the current value for the heat of formation of Am/O/sub 2/ and for the potential of the Am(III)-Am(IV) couple. The crystal structures and lattice parameters are reported for the trichloride, oxychloride and oxides of californium. (auth)

  14. Actinide burning and waste disposal

    Here we review technical and economic features of a new proposal for a synergistic waste-management system involving reprocessing the spent fuel otherwise destined for a U.S. high-level waste repository and transmuting the recovered actinides in a fast reactor. The proposal would require a U.S. fuel reprocessing plant, capable of recovering and recycling all actinides, including neptunium americium, and curium, from LWR spent fuel, at recoveries of 99.9% to 99.999%. The recovered transuranics would fuel the annual introduction of 14 GWe of actinide-burning liquid-metal fast reactors (ALMRs), beginning in the period 2005 to 2012. The new ALMRs would be accompanied by pyrochemical reprocessing facilities to recover and recycle all actinides from discharged ALMR fuel. By the year 2045 all of the LWR spent fuel now destined f a geologic repository would be reprocessed. Costs of constructing and operating these new reprocessing and reactor facilities would be borne by U.S. industry, from the sale of electrical energy produced. The ALMR program expects that ALMRs that burn actinides from LWR spent fuel will be more economical power producers than LWRs as early as 2005 to 2012, so that they can be prudently selected by electric utility companies for new construction of nuclear power plants in that era. Some leaders of DOE and its contractors argue that recovering actinides from spent fuel waste and burning them in fast reactors would reduce the life of the remaining waste to about 200-300 years, instead of 00,000 years. The waste could then be stored above ground until it dies out. Some argue that no geologic repositories would be needed. The current view expressed within the ALMR program is that actinide recycle technology would not replace the need for a geologic repository, but that removing actinides from the waste for even the first repository would simplify design and licensing of that repository. A second geologic repository would not be needed. Waste now planned

  15. Kinetics of actinide complexation reactions

    Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions

  16. 33rd Actinide Separations Conference

    McDonald, L M; Wilk, P A

    2009-05-04

    Welcome to the 33rd Actinide Separations Conference hosted this year by the Lawrence Livermore National Laboratory. This annual conference is centered on the idea of networking and communication with scientists from throughout the United States, Britain, France and Japan who have expertise in nuclear material processing. This conference forum provides an excellent opportunity for bringing together experts in the fields of chemistry, nuclear and chemical engineering, and actinide processing to present and discuss experiences, research results, testing and application of actinide separation processes. The exchange of information that will take place between you, and other subject matter experts from around the nation and across the international boundaries, is a critical tool to assist in solving both national and international problems associated with the processing of nuclear materials used for both defense and energy purposes, as well as for the safe disposition of excess nuclear material. Granlibakken is a dedicated conference facility and training campus that is set up to provide the venue that supports communication between scientists and engineers attending the 33rd Actinide Separations Conference. We believe that you will find that Granlibakken and the Lake Tahoe views provide an atmosphere that is stimulating for fruitful discussions between participants from both government and private industry. We thank the Lawrence Livermore National Laboratory and the United States Department of Energy for their support of this conference. We especially thank you, the participants and subject matter experts, for your involvement in the 33rd Actinide Separations Conference.

  17. MICROBIAL TRANSFORMATIONS OF PLUTONIUM AND OTHER ACTINIDES IN TRANSURANIC AND MIXED WASTES

    The presence of the actinides Th, U, Np, Pu, and Am in transuranic (TRU) and mixed wastes is a major concern because of their potential for migration from the waste repositories and long-term contamination of the environment. The toxicity of the actinide elements and the long half-lives of their isotopes are the primary causes for concern. In addition to the radionuclides the TRU waste consists a variety of organic materials (cellulose, plastic, rubber, chelating agents) and inorganic compounds (nitrate and sulfate). Significant microbial activity is expected in the waste because of the presence of organic compounds and nitrate, which serve as carbon and nitrogen sources and in the absence of oxygen the microbes can use nitrate and sulfate as alternate electron acceptors. Biodegradation of the TRU waste can result in gas generation and pressurization of containment areas, and waste volume reduction and subsidence in the repository. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of actinides have been investigated, we have only limited information on the effects of microbial processes. Microbial activity could affect the chemical nature of the actinides by altering the speciation, solubility and sorption properties and thus could increase or decrease the concentrations of actinides in solution. Under appropriate conditions, dissolution or immobilization of actinides is brought about by direct enzymatic or indirect non-enzymatic actions of microorganisms. Dissolution of actinides by microorganisms is brought about by changes in the Eh and pH of the medium, by their production of organic acids, such as citric acid, siderophores and extracellular metabolites. Immobilization or precipitation of actinides is due to changes in the Eh of the environment, enzymatic reductive precipitation (reduction from higher to lower oxidation state), biosorption, bioaccumulation, biotransformation of actinides complexed

  18. Actinide-specific sequestering agents and decontamination applications

    Smith, William L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials and Molecular Research Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Raymond, Kenneth N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials and Molecular Research Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1981-04-07

    With the commercial development of nuclear reactors, the actinides have become very important industrial elements. A major concern of the nuclear industry is the biological hazard associated with nuclear fuels and their wastes. The acute chemical toxicity of tetravalent actinides, as exemplified by Th(IV), is similar to Cr(III) or Al(III). However, the acute toxicity of 239Pu(IV) is similar to strychnine, which is much more toxic than any of the non-radioactive metals such as mercury. Although the more radioactive isotopes of the transuranium elements are more acutely toxic by weight than plutonium, the acute toxicities of 239Pu, 241Am, and 244Cm are nearly identical in radiation dose, ~100 μCi/kg in rodents. Finally and thus, the extreme acute toxicity of 239Pu is attributed to its high specific activity of alpha emission.

  19. Contents

    Editor IJRED

    2012-11-01

    Full Text Available International Journal of Renewable Energy Development www.ijred.com Volume 1             Number 3            October 2012                ISSN 2252- 4940   CONTENTS OF ARTICLES page Design and Economic Analysis of a Photovoltaic System: A Case Study 65-73 C.O.C. Oko , E.O. Diemuodeke, N.F. Omunakwe, and E. Nnamdi     Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review 75-80 W.D.P Rengga , M. Sudibandriyo and M. Nasikin     Process Optimization for Ethyl Ester Production in Fixed Bed Reactor Using Calcium Oxide Impregnated Palm Shell Activated Carbon (CaO/PSAC 81-86 A. Buasri , B. Ksapabutr, M. Panapoy and N. Chaiyut     Wind Resource Assessment in Abadan Airport in Iran 87-97 Mojtaba Nedaei       The Energy Processing by Power Electronics and its Impact on Power Quality 99-105 J. E. Rocha and B. W. D. C. Sanchez       First Aspect of Conventional Power System Assessment for High Wind Power Plants Penetration 107-113 A. Merzic , M. Music, and M. Rascic   Experimental Study on the Production of Karanja Oil Methyl Ester and Its Effect on Diesel Engine 115-122 N. Shrivastava,  , S.N. Varma and M. Pandey  

  20. Thermal-hydraulics of actinide burner reactors

    As a part of conceptual study of actinide burner reactors, core thermal-hydraulic analyses were conducted for two types of reactor concepts, namely (1) sodium-cooled actinide alloy fuel reactor, and (2) helium-cooled particle-bed reactor, to examine the feasibility of high power-density cores for efficient transmutation of actinides within the maximum allowable temperature limits of fuel and cladding. In addition, calculations were made on cooling of actinide fuel assembly. (author)

  1. Actinides and Life's Origins.

    Adam, Zachary

    2007-12-01

    There are growing indications that life began in a radioactive beach environment. A geologic framework for the origin or support of life in a Hadean heavy mineral placer beach has been developed, based on the unique chemical properties of the lower-electronic actinides, which act as nuclear fissile and fertile fuels, radiolytic energy sources, oligomer catalysts, and coordinating ions (along with mineralogically associated lanthanides) for prototypical prebiotic homonuclear and dinuclear metalloenzymes. A four-factor nuclear reactor model was constructed to estimate how much uranium would have been required to initiate a sustainable fission reaction within a placer beach sand 4.3 billion years ago. It was calculated that about 1-8 weight percent of the sand would have to have been uraninite, depending on the weight percent, uranium enrichment, and quantity of neutron poisons present within the remaining placer minerals. Radiolysis experiments were conducted with various solvents with the use of uraniumand thorium-rich minerals (metatorbernite and monazite, respectively) as proxies for radioactive beach sand in contact with different carbon, hydrogen, oxygen, and nitrogen reactants. Radiation bombardment ranged in duration of exposure from 3 weeks to 6 months. Low levels of acetonitrile (estimated to be on the order of parts per billion in concentration) were conclusively identified in 2 setups and tentatively indicated in a 3(rd) by gas chromatography/mass spectrometry. These low levels have been interpreted within the context of a Hadean placer beach prebiotic framework to demonstrate the promise of investigating natural nuclear reactors as power production sites that might have assisted the origins of life on young rocky planets with a sufficiently differentiated crust/mantle structure. Future investigations are recommended to better quantify the complex relationships between energy release, radioactive grain size, fissionability, reactant phase, phosphorus

  2. ALMR potential for actinide consumption

    The Advanced Liquid Metal Reactor (ALMR) is a US Department of Energy (DOE) sponsored fast reactor design based on the Power Reactor, Innovative Small Module (PRISM) concept originated by General Electric. This reactor combines a high degree of passive safety characteristics with a high level of modularity and factory fabrication to achieve attractive economics. The current reference design is a 471 MWt modular reactor fueled with ternary metal fuel. This paper discusses actinide transmutation core designs that fit the design envelope of the ALMR and utilize spent LWR fuel as startup material and for makeup. Actinide transmutation may be accomplished in the ALMR core by using either a breeding or burning configuration. Lifetime actinide mass consumption is calculated as well as changes in consumption behavior throughout the lifetime of the reactor. Impacts on system operational and safety performance are evaluated in a preliminary fashion. Waste disposal impacts are discussed. (author)

  3. Criticality and thermal analyses of separated actinides

    Curium and americium pose special problems in the chemical preparation of spent fuel for transmutation. Once separated from the other actinides, the isotopes can lead to nuclear fission with the subsequent release of a large amount of radiation. A neutron criticality code was used to determine keff for varying quantities of Cm2O3 and Am2O3 held within spherical or cylindrical containers. These geometries were investigated both in air and in water. Recommendations are made on the maximum amount of Cm2O3 and Am2O3 that can be safely stored or handled before encountering criticality. Several isotopes of curium and americium also generate a significant amount of heat by radioactive decay. If kilogram quantities are stored in a container, for example, the material may heat to an equilibrium temperature that exceeds its melting temperature. The heat generation of curium and americium present even more restriction on the mass of that can safely be contained in one location. (author)

  4. Improved Actinide Neutron Capture Cross Sections Using Accelerator Mass Spectrometry

    Bauder, W.; Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Nusair, O.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Collon, P.; Paul, M.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2014-09-01

    The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are

  5. Assessing the dietary sources of two cichlid species in River Nile sub-branches: Stomach contents, fatty acids and stable isotopes analyses

    Mohamad S. Abd El-Karim

    2016-06-01

    Full Text Available We assess the importance of four different food sources as dietary components of Oreochromis niloticus and Sarotherodon galilaeus in Nile sub-branches using stomach contents, fatty acids (FA and stable isotopes (SI analyses. Diatoms were the dominant food items, whereas sand and mud constitute a major part of the stomach contents of both cichlids in the northern ElBehery canal. FAs and SI were compared in cichlids and four potential food sources. Carbon isotopes excluded the fresh macrophyte Myriophyllum spicatum and its epiphytes as a potential food source, whereas FA biomarkers indicated that M. spicatum is assimilated in cichlids’ muscles as detrital materials. FA profiles of cichlids’ muscles were highly enriched by live diatom markers whereas decayed diatoms and bacterial markers were partially present. Carbon isotope signatures of cichlids were much close to that of suspended particulate organic matter (SPOM which elucidated that SPOM was the source of diatoms and bacterial detritus incorporated in cichlids muscles. Cichlids were highly enriched with nitrogen signatures which was a result of increased anthropogenic effects and incorporation of bacterial films. SI and FA analyses precisely indicated that live diatoms and bacteria, detrital macrophytes are the main sources of organic matter incorporated in cichlids muscles.

  6. Supercritical fluid extraction of actinide element complexes. II. SCF of actinide complexes with β-diketones

    Data on solubility of β-diketones complexes with uranium (VI), plutonium, neptunium, and americium in supercritical carbon dioxide (SC-CO2) are presented. It is established that content of actinide complexes with β-diketones in SC-CO2 can achieve 10-100 g/l. Complexes with dipivaloylmethane, trifluoroacetylacetone and hexafluoroacetylacetone and adducts with tributylphosphate and water in particular are the most highly soluble in it. Residues of complexes after dissolution in SC-CO2 are investigated spectroscopically

  7. Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

    Ramos D; Rodríguez-Tajes C.; Caamaño M.; Farget F.; Audouin L.; Benlliure J.; Casarejos E.; Clement E.; Cortina D.; Delaune O.; Derkx X.; Dijon A.; Doré D.; Fernández-Domínguez B.; France G. de

    2015-01-01

    Experimental access to full isotopic fragment distributions is very important to determine the features of the fission process. However, the isotopic identification of fission fragments has been, in the past, partial and scarce. A solution based on the use of inverse kinematics to study transfer-induced fission of exotic actinides was carried out at GANIL, resulting in the first experiment accessing the full identification of a collection of fissioning systems and their corresponding fission ...

  8. Actinide cation-cation complexes

    The +5 oxidation state of U, Np, Pu, and Am is a linear dioxo cation (AnO2+) with a formal charge of +1. These cations form complexes with a variety of other cations, including actinide cations. Other oxidation states of actinides do not form these cation-cation complexes with any cation other than AnO2+; therefore, cation-cation complexes indicate something unique about AnO2+ cations compared to actinide cations in general. The first cation-cation complex, NpO2+·UO22+, was reported by Sullivan, Hindman, and Zielen in 1961. Of the four actinides that form AnO2+ species, the cation-cation complexes of NpO2+ have been studied most extensively while the other actinides have not. The only PuO2+ cation-cation complexes that have been studied are with Fe3+ and Cr3+ and neither one has had its equilibrium constant measured. Actinides have small molar absorptivities and cation-cation complexes have small equilibrium constants; therefore, to overcome these obstacles a sensitive technique is required. Spectroscopic techniques are used most often to study cation-cation complexes. Laser-Induced Photacoustic Spectroscopy equilibrium constants for the complexes NpO2+·UO22+, NpO2+·Th4+, PuO2+·UO22+, and PuO2+·Th4+ at an ionic strength of 6 M using LIPAS are 2.4 ± 0.2, 1.8 ± 0.9, 2.2 ± 1.5, and ∼0.8 M-1

  9. Orbital effects in actinide systems

    Actinide magnetism presents a number of important challenges; in particular, the proximity of 5f band to the Fermi energy gives rise to strong interaction with both d and s like conduction electrons, and the extended nature of the 5f electrons means that they can interact with electron orbitals from neighboring atoms. Theory has recently addressed these problems. Often neglected, however, is the overwhelming evidence for large orbital contributions to the magnetic properties of actinides. Some experimental evidence for these effects are presented briefly in this paper. They point, clearly incorrectly, to a very localized picture for the 5f electrons. This dichotomy only enhances the nature of the challenge

  10. Fabrication of actinide mononitride fuel

    Fabrication of actinide mononitride fuel in JAERI is summarized. Actinide mononitride and their solid solutions were fabricated by carbothermic reduction of the oxides in N2 or N2-H2 mixed gas stream. Sintering study was also performed for the preparation of pellets for the property measurements and irradiation tests. The products were characterized to be high-purity mononitride with a single phase of NaCl-type structure. Moreover, fuel pins containing uranium-plutonium mixed nitride pellets were fabricated for the irradiation tests in JMTR and JOYO. (author)

  11. Trophic interactions of common elasmobranchs in deep-sea communities of the Gulf of Mexico revealed through stable isotope and stomach content analysis

    Churchill, Diana A.; Heithaus, Michael R.; Vaudo, Jeremy J.; Grubbs, R. Dean; Gastrich, Kirk; Castro, José I.

    2015-05-01

    Deep-water sharks are abundant and widely distributed in the northern and eastern Gulf of Mexico. As mid- and upper-level consumers that can range widely, sharks likely are important components of deep-sea communities and their trophic interactions may serve as system-wide baselines that could be used to monitor the overall health of these communities. We investigated the trophic interactions of deep-sea sharks using a combination of stable isotope (δ13C and δ15N) and stomach content analyses. Two hundred thirty-two muscle samples were collected from elasmobranchs captured off the bottom at depths between 200 and 1100 m along the northern slope (NGS) and the west Florida slope (WFS) of the Gulf of Mexico during 2011 and 2012. Although we detected some spatial, temporal, and interspecific variation in apparent trophic positions based on stable isotopes, there was considerable isotopic overlap among species, between locations, and through time. Overall δ15N values in the NGS region were higher than in the WFS. The δ15N values also increased between April 2011 and 2012 in the NGS, but not the WFS, within Squalus cf. mitsukurii. We found that stable isotope values of S. cf. mitsukurii, the most commonly captured elasmobranch, varied between sample regions, through time, and also with sex and size. Stomach content analysis (n=105) suggested relatively similar diets at the level of broad taxonomic categories of prey among the taxa with sufficient sample sizes. We did not detect a relationship between body size and relative trophic levels inferred from δ15N, but patterns within several species suggest increasing trophic levels with increasing size. Both δ13C and δ15N values suggest a substantial degree of overlap among most deep-water shark species. This study provides the first characterization of the trophic interactions of deep-sea sharks in the Gulf of Mexico and establishes system baselines for future investigations.

  12. Testing of an automated online EA-IRMS method for fast and simultaneous carbon content and stable isotope measurement of aerosol samples

    Major, István; Gyökös, Brigitta; Túri, Marianna; Futó, István; Filep, Ágnes; Hoffer, András; Molnár, Mihály

    2016-04-01

    Comprehensive atmospheric studies have demonstrated that carbonaceous aerosol is one of the main components of atmospheric particulate matter over Europe. Various methods, considering optical or thermal properties, have been developed for quantification of the accurate amount of both organic and elemental carbon constituents of atmospheric aerosol. The aim of our work was to develop an alternative fast and easy method for determination of the total carbon content of individual aerosol samples collected on prebaked quartz filters whereby the mass and surface concentration becomes simply computable. We applied the conventional "elemental analyzer (EA) coupled online with an isotope ratio mass spectrometer (IRMS)" technique which is ubiquitously used in mass spectrometry. Using this technique we are able to measure simultaneously the carbon stable isotope ratio of the samples, as well. During the developing process, we compared the EA-IRMS technique with an off-line catalytic combustion method worked out previously at Hertelendi Laboratory of Environmental Studies (HEKAL). We tested the combined online total carbon content and stable isotope ratio measurement both on standard materials and real aerosol samples. Regarding the test results the novel method assures, on the one hand, at least 95% of carbon recovery yield in a broad total carbon mass range (between 100 and 3000 ug) and, on the other hand, a good reproducibility of stable isotope measurements with an uncertainty of ± 0.2 per mill. Comparing the total carbon results obtained by the EA-IRMS and the off-line catalytic combustion method we found a very good correlation (R2=0.94) that proves the applicability of both preparation method. Advantages of the novel method are the fast and simplified sample preparation steps and the fully automated, simultaneous carbon stable isotope ratio measurement processes. Furthermore stable isotope ratio results can effectively be applied in the source apportionment

  13. Chemistry of tetravalent actinides phosphates. The thorium phosphate-diphosphate as immobilisation matrix of actinides

    The author presents in this document its scientific works from 1992 to 2001, in order to obtain the enabling to manage scientific and chemical researches at the university Paris Sud Orsay. The first part gives an abstract of the thesis on the characterizations, lixiviation and synthesis of uranium and thorium based phosphate matrix in the framework of the search for a ceramic material usable in the radioactive waste storage. The second part presents briefly the researches realized at the CEA, devoted to a reliable, independent and accurate measure of some isotopes activity. The last part presents the abstracts of researches activities from 1996 to 2001 on the tetravalent actinides phosphates chemistry, the sintering of PDT and solid solutions of PDTU and the kinetic and thermodynamical studies of the PDT dissolution. Many references and some publication in full text are provided. (A.L.B.)

  14. Reference measurements for total mercury and methyl mercury content in marine biota samples using direct or species-specific isotope dilution inductively coupled plasma mass spectrometry.

    Krata, Agnieszka; Vassileva, Emilia; Bulska, Ewa

    2016-11-01

    The analytical procedures for reference measurements of the total Hg and methyl mercury (MeHg) mass fractions at various concentration levels in marine biota samples, candidates for certified reference materials (oyster and clam Gafrarium tumidum), were evaluated. Two modes of application of isotope dilution inductively coupled plasma mass spectrometry method (ID ICP-MS), namely direct isotope dilution and species-specific isotope dilution analysis with the use of two different quantification mass spectrometry techniques were compared. The entire ID ICP-MS measurement procedure was described by mathematical modelling and the combined uncertainty of measurement results was estimated. All factors influencing the final results as well as isotopic equilibrium were systematically investigated. This included the procedural blank, the moisture content in the biota samples and all factors affecting the blend ratio measurements (instrumental background, spectral interferences, dead time and mass discrimination effects as well as the repeatability of measured isotopic ratios). Modelling of the entire measurement procedures and the use of appropriate certified reference materials enable to assure the traceability of obtained values to the International System of Units (SI): the mole or the kilogram. The total mass fraction of mercury in oyster and clam biota samples, after correction for moisture contents, was found to be: 21.1 (1.1) 10(-9) kg kg(-1) (U =5.1% relative, k=2) and 390.0 (9.4) 10(-9) kg kg(-1) (U=2.4% relative, k=2), respectively. For the determination of mercury being present as methyl mercury, the non-chromatographic separation on anion-exchange resin AG1-X8 of the blended samples was applied. The content of MeHg (as Hg) in oyster sample was found: 4.81 (24) 10(-9)kgkg(-1) (U=5.0%, k=2) and 4.84 (21) 10(-9)kgkg(-1) (U=4.3%, k=2) with the use of quadrupole (ICP QMS) or sector field (ICP SFMS) inductively coupled plasma mass spectrometers, respectively. In the

  15. Environmental research on actinide elements

    Pinder, J.E. III; Alberts, J.J.; McLeod, K.W.; Schreckhise, R.G. (eds.)

    1987-08-01

    The papers synthesize the results of research sponsored by DOE's Office of Health and Environmental Research on the behavior of transuranic and actinide elements in the environment. Separate abstracts have been prepared for the 21 individual papers. (ACR)

  16. Relationships among Water Use Efficiency, Grain Yield, Carbon Isotope Discrimination and Ash Content in Wheat under Different Mega-Environments and Water Regimes in China and India

    Positive correlations have been repeatedly reported between grain yield, carbon isotope discrimination (CID, Δ13C or Δ) and ash content in wheat cultivated under Mediterranean-type environments (characterized by post-anthesis water stress). The relationships among these traits have been much less analyzed under other wheat mega-environments. The present study examined the relationships between grain yield, Δ13C and ash content in wheat in Northern China (characterized by pre-anthesis water stress) and in the Peninsular Zone of India (characterized by residual moisture stress). In both mega-environments, wheat was grown under rain fed and irrigated conditions. The relationships between grain yield, Δ and ash content were less stable than under post-anthesis water stress, and were highly dependent on the quantity of water stored in the soil at sowing, which in turn depends on out-of-season rainfall. This considerably limits the use of Δ and ash content as indirect selection criteria for yield in these mega-environments. In India, the relationships between Δ, ash content and components of water use efficiency (WUE) (the latter were estimated from a soil water balance model) were also investigated. Significant correlations were found across environments between ash content in leaf and grain and the model estimates of the quantity of water transpired during the growth cycle. WUE was significantly negatively correlated with ash content in leaf and grain. Additional analyses of the relationships among grain yield, Δ and ash content, including soil moisture measurements over the growing period and/or estimation of water balance components, are needed in these mega-environments to define precisely the range of conditions leading to significant correlations and allowing the use of Δ and ash content as indirect selection criteria for yield. (author)

  17. Innovative SANEX process for trivalent actinides separation from PUREX raffinate

    Recycling of nuclear spent fuel and reduction of its radiotoxicity by separation of long-lived radionuclides would definitely help to close the nuclear fuel cycle ensuring sustainability of the nuclear energy. Partitioning of the main radiotoxicity contributors followed by their conversion into short-lived radioisotopes is known as partitioning and transmutation strategy. To ensure efficient transmutation of the separated elements (minor actinides) the content of lanthanides in the irradiation targets has to be minimised. This objective can be attained by solvent extraction using highly selective ligands that are able to separate these two groups of elements from each other. The objective of this study was to develop a novel process allowing co-separation of minor actinides and lanthanides from a high active acidic feed solution with subsequent actinide recovery using just one cycle, so-called innovative SANEX process. The conditions of each step of the process were optimised to ensure high actinide separation efficiency. Additionally, screening tests of several novel lipophilic and hydrophilic ligands provided by University of Twente were performed. These tests were aiming in better understanding the influence of the extractant structural modifications onto An(III)/Ln(III) selectivity and complexation properties. Optimal conditions for minor actinides separation were found and a flow-sheet of a new innovative SANEX process was proposed. Tests using a single centrifugal contactor confirmed high Eu(III)/Am(III) separation factor of 15 while the lowest SFLn/Am obtained was 6,5 (for neodymium). In addition, a new masking agent for zirconium was found as a substitution for oxalic acid. This new masking agent (CDTA) was also able to mask palladium without any negative influence on An(III)/Ln(III). Additional tests showed no influence of CDTA on plutonium present in the feed solution unlike oxalic acid which causes Pu precipitation. Therefore, CDTA was proposed as a Zr

  18. Innovative SANEX process for trivalent actinides separation from PUREX raffinate

    Sypula, Michal

    2013-07-01

    Recycling of nuclear spent fuel and reduction of its radiotoxicity by separation of long-lived radionuclides would definitely help to close the nuclear fuel cycle ensuring sustainability of the nuclear energy. Partitioning of the main radiotoxicity contributors followed by their conversion into short-lived radioisotopes is known as partitioning and transmutation strategy. To ensure efficient transmutation of the separated elements (minor actinides) the content of lanthanides in the irradiation targets has to be minimised. This objective can be attained by solvent extraction using highly selective ligands that are able to separate these two groups of elements from each other. The objective of this study was to develop a novel process allowing co-separation of minor actinides and lanthanides from a high active acidic feed solution with subsequent actinide recovery using just one cycle, so-called innovative SANEX process. The conditions of each step of the process were optimised to ensure high actinide separation efficiency. Additionally, screening tests of several novel lipophilic and hydrophilic ligands provided by University of Twente were performed. These tests were aiming in better understanding the influence of the extractant structural modifications onto An(III)/Ln(III) selectivity and complexation properties. Optimal conditions for minor actinides separation were found and a flow-sheet of a new innovative SANEX process was proposed. Tests using a single centrifugal contactor confirmed high Eu(III)/Am(III) separation factor of 15 while the lowest SF{sub Ln/Am} obtained was 6,5 (for neodymium). In addition, a new masking agent for zirconium was found as a substitution for oxalic acid. This new masking agent (CDTA) was also able to mask palladium without any negative influence on An(III)/Ln(III). Additional tests showed no influence of CDTA on plutonium present in the feed solution unlike oxalic acid which causes Pu precipitation. Therefore, CDTA was proposed as

  19. Detection of the actinides and cesium from environmental samples

    Snow, Mathew Spencer

    Detection of the actinides and cesium in the environment is important for a variety of applications ranging from environmental remediation to safeguards and nuclear forensics. The utilization of multiple different elemental concentrations and isotopic ratios together can significantly improve the ability to attribute contamination to a unique source term and/or generation process; however, the utilization of multiple elemental "signatures" together from environmental samples requires knowledge of the impact of chemical fractionation for various elements under a variety of environmental conditions (including predominantly aqueous versus arid conditions). The research reported in this dissertation focuses on three major areas: 1. Improving the understanding of actinide-mineral interactions at ultra-low concentrations. Chapter 2 reports a batch sorption and modeling study of Np(V) sorption to the mineral goethite from attomolar to micromolar concentrations. 2. Improving the detection capabilities for Thermal Ionization Mass Spectrometry (TIMS) analyses of ultra-trace cesium from environmental samples. Chapter 4 reports a new method which significantly improves the chemical yields, purification, sample processing time, and ultimately, the detection limits for TIMS analyses of femtogram quantities of cesium from a variety of environmental sample matrices. 3. Demonstrating how actinide and cesium concentrations and isotopic ratios from environmental samples can be utilized together to determine a wealth of information including environmental transport mechanisms (e.g. aqueous versus arid transport) and information on the processes which generated the original material. Chapters1, 3 and 5 demonstrate these principles using Pu, Am, Np, and Cs concentrations and isotopic ratios from contaminated soils taken near the Subsurface Disposal Area (SDA) of Idaho National Laboratory (INL) (a low level radioactive waste disposal site in southeastern Idaho).

  20. Benchmark analyses for BN-600 MOX core with minor actinides

    Full text: The IAEA has initiated in 1999 a Coordinated Research Project (CRP) on 'Updated Codes and Methods to Reduce the Calculational Uncertainties of the LMFR Reactivity Effects'. The general objective of the CRP is to validate, verify and improve methodologies and computer codes used for calculation of reactivity coefficients in fast reactors aiming at enhancing the utilization of plutonium and minor actinides (MAs). For this purpose, three benchmark models representing different modifications of the BN-600 reactor UOX core have been sequentially established and analyzed,the benchmark specifications being provided by IPPE. The first benchmark model is a hybrid UOX/MOX core, with UOX fuel in the inner core part and MOX fuel in the outer one, the fresh MOX fuel containing depleted uranium and weapons grade plutonium. The second model is a full MOX core, similar MOX fuel composition being assumed; a sodium plenum being introduced above the core to improve the core safety. The third model is analyzed in the paper. The model represents a similar full MOX core, but with plutonium and MAs from 60 GWd/t LWR spent fuel after 50 years cooling (thus assuming a so-called homogeneous recycling of MAs in a fast system). This option is the most challenging one (compared to those analyzed earlier in the CRP) as concerns the reactor safety since an increased content of MAs, in particular americium, and higher (than Pu239) isotopes of Pu leads to less favourable safety parameters. On the other hand, existing uncertainties in nuclear data for MAs and higher Pu isotopes may lead to relatively high uncertainties in the computation results for the considered model. The benchmark results include core criticality at the beginning and end of the equilibrium fuel cycle, kinetics parameters, spatial distributions of power and reactivity coefficients provided by CRP participants and obtained by employing different computation models and nuclear data. Sensitivity studies were performed at

  1. C-14 and Ar-39 content in a ground water aquifer in the Saarland - comparison of two ground water isotope dating methods

    For the Ar-39 groundwater ages found an age comparison is made with ground waters investigated for C-14, Kr-85 and H-3 contents. The location of investigation is a sandstone aquifer of Southern Saarland. The underground production of Ar-39 the hydrological applicability. In granite, the average concentration of U, Th, K, and Cl with an average porosity of 1% and complete diffusion of the isotopes Ar-39 and Cl-36 produced underground can be as high as 105% for Ar-39 moderated and 16% Cl-36 moderated in the interstitial water. (DG)

  2. Behavior of actinides in the Integral Fast Reactor fuel cycle

    Courtney, J.C. [Louisiana State Univ., Baton Rouge, LA (United States). Nuclear Science Center; Lineberry, M.J. [Argonne National Lab., Idaho Falls, ID (United States). Technology Development Div.

    1994-06-01

    The Integral Fast Reactor (IFR) under development by Argonne National Laboratory uses metallic fuels instead of ceramics. This allows electrorefining of spent fuels and presents opportunities for recycling minor actinide elements. Four minor actinides ({sup 237}Np, {sup 240}Pu, {sup 241}Am, and {sup 243}Am) determine the waste storage requirements of spent fuel from all types of fission reactors. These nuclides behave the same as uranium and other plutonium isotopes in electrorefining, so they can be recycled back to the reactor without elaborate chemical processing. An experiment has been designed to demonstrate the effectiveness of the high-energy neutron spectra of the IFR in consuming these four nuclides and plutonium. Eighteen sets of seven actinide and five light metal targets have been selected for ten day exposure in the Experimental Breeder Reactor-2 which serves as a prototype of the IFR. Post-irradiation analyses of the exposed targets by gamma, alpha, and mass spectroscopy are used to determine nuclear reaction-rates and neutron spectra. These experimental data increase the authors` confidence in their ability to predict reaction rates in candidate IFR designs using a variety of neutron transport and diffusion programs.

  3. Behavior of actinides in the Integral Fast Reactor fuel cycle

    The Integral Fast Reactor (IFR) under development by Argonne National Laboratory uses metallic fuels instead of ceramics. This allows electrorefining of spent fuels and presents opportunities for recycling minor actinide elements. Four minor actinides (237Np, 240Pu, 241Am, and 243Am) determine the waste storage requirements of spent fuel from all types of fission reactors. These nuclides behave the same as uranium and other plutonium isotopes in electrorefining, so they can be recycled back to the reactor without elaborate chemical processing. An experiment has been designed to demonstrate the effectiveness of the high-energy neutron spectra of the IFR in consuming these four nuclides and plutonium. Eighteen sets of seven actinide and five light metal targets have been selected for ten day exposure in the Experimental Breeder Reactor-2 which serves as a prototype of the IFR. Post-irradiation analyses of the exposed targets by gamma, alpha, and mass spectroscopy are used to determine nuclear reaction-rates and neutron spectra. These experimental data increase the authors' confidence in their ability to predict reaction rates in candidate IFR designs using a variety of neutron transport and diffusion programs

  4. Actinide behavior in the Integral Fast Reactor. Final project report

    The Integral Fast Reactor (IFR) under development by Argonne National Laboratory uses metallic fuels instead of ceramics. This allows electrorefining of spent fuels and presents opportunities for recycling minor actinide elements. Four minor actinides (237Np, 240Pu, 241Am, and 243Am) determine the waste storage requirements of spent fuel from all types of fission reactors. These nuclides behave the same as uranium and other plutonium isotopes in electrorefining, so they can be recycled back to the reactor without elaborate chemical processing. An experiment has been designed to demonstrate the effectiveness of the high-energy neutron spectra of the IFR in consuming these four nuclides and weapons grade plutonium. Eighteen sets of seven actinide and five light metal targets have been selected for seven day exposure in the Experimental Breeder Reactor-II which serves as a prototype of the IFR. Post-irradiation analyses of the exposed targets by gamma, alpha, and mass spectroscopy are used to determine nuclear reaction rates and neutron spectra. These experimental data increase the authors confidence in their ability to predict reaction rates in candidate IFR designs using a variety of neutron transport and diffusion programs

  5. Toward laser ablation Accelerator Mass Spectrometry of actinides

    A project to measure neutron capture cross sections of a number of actinides in a reactor environment by Accelerator Mass Spectrometry (AMS) at the ATLAS facility of Argonne National Laboratory is underway. This project will require the precise and accurate measurement of produced actinide isotopes in many (>30) samples irradiated in the Advanced Test Reactor at Idaho National Laboratory with neutron fluxes having different energy distributions. The AMS technique at ATLAS is based on production of highly-charged positive ions in an electron cyclotron resonance (ECR) ion source followed by acceleration in the ATLAS linac and mass-to-charge (m/q) measurement at the focus of the Fragment Mass Analyzer. Laser ablation was selected as the method of feeding the actinide material into the ion source because we expect it will have higher efficiency and lower chamber contamination than either the oven or sputtering techniques, because of a much narrower angular distribution of emitted material. In addition, a new multi-sample holder/changer to allow quick change between samples and a computer-controlled routine allowing fast tuning of the accelerator for different beams, are being developed. An initial test run studying backgrounds, detector response, and accelerator scaling repeatability was conducted in December 2010. The project design, schedule, and results of the initial test run to study backgrounds are discussed.

  6. Toward laser ablation Accelerator Mass Spectrometry of actinides

    Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Paul, M.; Collon, P.; Deibel, C.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Fonnesbeck, J.; Imel, G.

    2013-01-01

    A project to measure neutron capture cross sections of a number of actinides in a reactor environment by Accelerator Mass Spectrometry (AMS) at the ATLAS facility of Argonne National Laboratory is underway. This project will require the precise and accurate measurement of produced actinide isotopes in many (>30) samples irradiated in the Advanced Test Reactor at Idaho National Laboratory with neutron fluxes having different energy distributions. The AMS technique at ATLAS is based on production of highly-charged positive ions in an electron cyclotron resonance (ECR) ion source followed by acceleration in the ATLAS linac and mass-to-charge (m/q) measurement at the focus of the Fragment Mass Analyzer. Laser ablation was selected as the method of feeding the actinide material into the ion source because we expect it will have higher efficiency and lower chamber contamination than either the oven or sputtering techniques, because of a much narrower angular distribution of emitted material. In addition, a new multi-sample holder/changer to allow quick change between samples and a computer-controlled routine allowing fast tuning of the accelerator for different beams, are being developed. An initial test run studying backgrounds, detector response, and accelerator scaling repeatability was conducted in December 2010. The project design, schedule, and results of the initial test run to study backgrounds are discussed.

  7. Isotopic evidence of TSR origin for natural gas bearing high H2S contents within the Feixianguan Formation of the northeastern Sichuan Basin, southwestern China

    ZHU Guangyou; ZHANG Shuichang; LIANG Yingbo; DAI Jinxing; LI Jian

    2005-01-01

    The northeastern area of Sichuan Basin, southwestern China, is the area with the maximal reserve of natural gas containing higher hydrogen sulphide (H2S) that has been found among the petroliferous basins of China, with the proven and controlled gas reserve of more than 200 billion cubic meters. These gas pools, with higher H2S contents averaging 9%, some 17%, are mainly distributed on structural belts of Dukouhe, Tieshanpo, Luojiazhai, Puguang, etc., while the oolitic-shoal dolomite of the Triassic Feixianguan Fm. (T1f) is the reservoir. Although many scholars regard the plentiful accumulation of H2S within the deep carbonate reservoir as the result of Thermochemical Sulfate Reduction (TSR), however, the process of TSR as well as its residual geological and geochemical evidence is still not quite clear. Based on the carbon isotopic analysis of carbonate strata and secondary calcite, etc., together with the analysis of sulfur isotopes within H2S, sulphur, gypsum, iron pyrites, etc., as well as other aspects including the natural gas composition, carbon isotopes of hydrocarbons reservoir petrology, etc., it has been proved that the above natural gas is a product of TSR. The H2S, sulphur and calcite result from the participation of TSR reactions by hydrocarbon gas. During the process for hydrocarbons being consumed due to TSR, the carbons within the hydrocarbon gas participate in the reactions and finally are transferred into the secondary calcite, and become the carbon source of secondary calcite, consequently causing the carbon isotopes of the secondary calcite to be lower (-18.2‰). As for both the intermediate product of TSR, i.e. sulfur, and its final products, i.e. H2S and iron pyrites, their sulfur elements are all sourced from the sulfate within the Feixianguan Fm. During the fractional processes of sulfur isotopes, the bond energy leads to the 32S being released firstly, and the earlier it is released, the lower δ34S values for the generated sulphide (H2S

  8. Thermal ionization mass spectrometry for determinations of isotopic content and concentration of trace amounts of uranium in water samples

    There were some reports in the media that children from Faridkot area in Punjab suffered from abnormalities. Analyses of hair samples showed the presence of Sn, Pb, Al, Mn, Fe and U in a majority of samples. The levels of uranium were large enough to cause abnormalities. Presence of uranium prompted Department of Atomic Energy to take up these investigations. It was found that background radiation levels in Faridkot and surrounding districts of Punjab were normal and within the levels across India. We received two surface water samples for determination of uranium in these samples. This paper describes the methodologies that were used to determine isotopic composition of uranium present in trace amounts. The two in one methodology developed in this laboratory in the past using 233U as a spike was used. This method enabled the determination of isotopic composition and concentration of uranium from the same mass spectrometric analysis data

  9. Site-specific 13C content by quantitative isotopic 13C Nuclear Magnetic Resonance spectrometry: A pilot inter-laboratory study

    Graphical abstract: -- Highlights: •First ring test on isotopic 13C NMR spectrometry. •Evaluation of the intra- and inter-variability of the NMR spectrometers used. •Definition of a protocol for qualification of the performance of the spectrometer. -- Abstract: Isotopic 13C NMR spectrometry, which is able to measure intra-molecular 13C composition, is of emerging demand because of the new information provided by the 13C site-specific content of a given molecule. A systematic evaluation of instrumental behaviour is of importance to envisage isotopic 13C NMR as a routine tool. This paper describes the first collaborative study of intra-molecular 13C composition by NMR. The main goals of the ring test were to establish intra- and inter-variability of the spectrometer response. Eight instruments with different configuration were retained for the exercise on the basis of a qualification test. Reproducibility at the natural abundance of isotopic 13C NMR was then assessed on vanillin from three different origins associated with specific δ13Ci profiles. The standard deviation was, on average, between 0.9 and 1.2‰ for intra-variability. The highest standard deviation for inter-variability was 2.1‰. This is significantly higher than the internal precision but could be considered good in respect of a first ring test on a new analytical method. The standard deviation of δ13Ci in vanillin was not homogeneous over the eight carbons, with no trend either for the carbon position or for the configuration of the spectrometer. However, since the repeatability for each instrument was satisfactory, correction factors for each carbon in vanillin could be calculated to harmonize the results

  10. Site-specific {sup 13}C content by quantitative isotopic {sup 13}C Nuclear Magnetic Resonance spectrometry: A pilot inter-laboratory study

    Chaintreau, Alain; Fieber, Wolfgang; Sommer, Horst [Firmenich SA, Corporate R and D Division, P.O. Box 239, 1211 Geneva 8 (Switzerland); Gilbert, Alexis; Yamada, Keita [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Yoshida, Naohiro [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Pagelot, Alain [Bruker Biospin SAS, 34 rue de l‘Industrie, 67166 Wissembourg Cedex (France); Moskau, Detlef; Moreno, Aitor [Bruker Biospin AG, Industriestrasse 26, 8117 Fällanden (Switzerland); Schleucher, Jürgen [Department of Medical Biochemistry and Biophysics, Umeå University, S-90187 Umeå (Sweden); Reniero, Fabiano; Holland, Margaret; Guillou, Claude [European Commission, Joint Research Centre – Institute for Health and Consumer Protection, via E. Fermi 2749, I-21027 Ispra (Italy); Silvestre, Virginie; Akoka, Serge [EBSI team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Remaud, Gérald S., E-mail: gerald.remaud@univ-nantes.fr [EBSI team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France)

    2013-07-25

    Graphical abstract: -- Highlights: •First ring test on isotopic {sup 13}C NMR spectrometry. •Evaluation of the intra- and inter-variability of the NMR spectrometers used. •Definition of a protocol for qualification of the performance of the spectrometer. -- Abstract: Isotopic {sup 13}C NMR spectrometry, which is able to measure intra-molecular {sup 13}C composition, is of emerging demand because of the new information provided by the {sup 13}C site-specific content of a given molecule. A systematic evaluation of instrumental behaviour is of importance to envisage isotopic {sup 13}C NMR as a routine tool. This paper describes the first collaborative study of intra-molecular {sup 13}C composition by NMR. The main goals of the ring test were to establish intra- and inter-variability of the spectrometer response. Eight instruments with different configuration were retained for the exercise on the basis of a qualification test. Reproducibility at the natural abundance of isotopic {sup 13}C NMR was then assessed on vanillin from three different origins associated with specific δ{sup 13}C{sub i} profiles. The standard deviation was, on average, between 0.9 and 1.2‰ for intra-variability. The highest standard deviation for inter-variability was 2.1‰. This is significantly higher than the internal precision but could be considered good in respect of a first ring test on a new analytical method. The standard deviation of δ{sup 13}C{sub i} in vanillin was not homogeneous over the eight carbons, with no trend either for the carbon position or for the configuration of the spectrometer. However, since the repeatability for each instrument was satisfactory, correction factors for each carbon in vanillin could be calculated to harmonize the results.

  11. Actinides recycling assessment in a thermal reactor

    Highlights: • Actinides recycling is assessed using BWR fuel assemblies. • Four fuel rods are substituted by minor actinides rods in a UO2 and in a MOX fuel assembly. • Performance of standard fuel assemblies and the ones with the substitution is compared. • Reduction of actinides is measured for the fuel assemblies containing minor actinides rods. • Thermal reactors can be used for actinides recycling. - Abstract: Actinides recycling have the potential to reduce the geological repository burden of the high-level radioactive waste that is produced in a nuclear power reactor. The core of a standard light water reactor is composed only by fuel assemblies and there are no specific positions to allocate any actinides blanket, in this assessment it is proposed to replace several fuel rods by actinides blankets inside some of the reactor core fuel assemblies. In the first part of this study, a single uranium standard fuel assembly is modeled and the amount of actinides generated during irradiation is quantified for use it as reference. Later, in the same fuel assembly four rods containing 6 w/o of minor actinides and using depleted uranium as matrix were replaced and depletion was simulated to obtain the net reduction of minor actinides. Other calculations were performed using MOX fuel lattices instead of uranium standard fuel to find out how much reduction is possible to obtain. Results show that a reduction of minor actinides is possible using thermal reactors and a higher reduction is obtained when the minor actinides are embedded in uranium fuel assemblies instead of MOX fuel assemblies

  12. Gross actinide preconcentration using phosphonate-based ligand and cloud point extraction

    A procedure for the effective separation and determination of the most abundant actinides relevant to the nuclear industry (U, Th, Np, Pu and Am) was developed based on cloud point extraction (CPE) using H2DEH[MDP] (P,P-di-(2-ethylhexyl) methanediphosphonic acid) as a ligand. The extractability of actinides with varying concentrations of nitric acid and hydrochloric acid were assessed. The robustness of the method was demonstrated for environmental matrices such as reference materials and spiked liquid samples for the quantification of the gross actinide content. This analytical strategy may replace traditional sample preparation techniques used in radiological methods for gross measurements of radioactivity, and may act as a rapid screening tool in emergency situations. The developed method is a greener alternative to common radiochemical sample preparation techniques such as co-precipitation or evaporation. The formation of a small-volume surfactant-rich phase containing the complexed actinides enables rapid, highly selective and great enrichment of the analytes in this phase. The proposed method shows good extraction and separation yield compared to existing methods, since the surfactant-rich phase is soluble in water and can therefore be redispersed quantitatively in a medium compatible with mass spectrometry while providing fast isolation of the actinide content. Separation of actinides can be achieved after by wet ashing of the surfactant-rich phase obtained by CPE if coupled to the proper radiochemical separation scheme. (author)

  13. Synergistic extraction of actinides : Part II. Tetra-and trivalent actinides

    A detailed discussion on the synergistic solvent extraction behaviour of tetra- and trivalent actinide ions is presented. Structural aspects of the natural donor adducts of the tetravalent actinide ion chelates involved in synergism are also discussed. (author)

  14. Spin Hamiltonians for actinide ions

    The breakdown of Russel Saunders coupling for correlated f-levels of actinide ions is due to both spin orbit coupling and the crystalline electric field (CEF). Experiments on curium, an S-state ion in the metal for which the CEF is weak indicate a g-factor close to the Russel-Saunders value. Spin-orbit coupling is therefore too weak to produce jj coupling. This suggests a model for magnetic actinide ions in which the CEF ground multiplet is well separated from higher levels, completely determining thermodynamic magnetic properties. On this basis simplified spin Hamiltonians are derived for GAMMA1-GAMMA5 ground states in order to interpret thermodynamic measurements and ordering phenomena. (author)

  15. Actinide chemistry in ionic liquids.

    Takao, Koichiro; Bell, Thomas James; Ikeda, Yasuhisa

    2013-04-01

    This Forum Article provides an overview of the reported studies on the actinide chemistry in ionic liquids (ILs) with a particular focus on several fundamental chemical aspects: (i) complex formation, (ii) electrochemistry, and (iii) extraction behavior. The majority of investigations have been dedicated to uranium, especially for the 6+ oxidation state (UO2(2+)), because the chemistry of uranium in ordinary solvents has been well investigated and uranium is the most abundant element in the actual nuclear fuel cycles. Other actinides such as thorium, neptunium, plutonium, americium, and curiumm, although less studied, are also of importance in fully understanding the nuclear fuel engineering process and the safe geological disposal of radioactive wastes. PMID:22873132

  16. Actinide recovery techniques utilizing electromechanical processes

    Under certain conditions, the separation of actinides using electromechanical techniques may be an effective means of residue processing. The separation of granular mixtures of actinides and other materials discussed in this report is based on appreciable differences in the magnetic and electrical properties of the actinide elements. In addition, the high density of actinides, particularly uranium and plutonium, may render a simultaneous separation based on mutually complementary parameters. Both high intensity magnetic separation and electrostatic separation have been investigated for the concentration of an actinide waste stream. Waste stream constituents include an actinide metal alloy and broken quartz shards. The investigation of these techniques is in support of the Integral Fast Reactor (IFR) concept currently being developed at Argonne National Laboratory under the auspices of the Department of Energy

  17. Actinide Waste Forms and Radiation Effects

    Ewing, R. C.; Weber, W. J.

    Over the past few decades, many studies of actinides in glasses and ceramics have been conducted that have contributed substantially to the increased understanding of actinide incorporation in solids and radiation effects due to actinide decay. These studies have included fundamental research on actinides in solids and applied research and development related to the immobilization of the high level wastes (HLW) from commercial nuclear power plants and processing of nuclear weapons materials, environmental restoration in the nuclear weapons complex, and the immobilization of weapons-grade plutonium as a result of disarmament activities. Thus, the immobilization of actinides has become a pressing issue for the twenty-first century (Ewing, 1999), and plutonium immobilization, in particular, has received considerable attention in the USA (Muller et al., 2002; Muller and Weber, 2001). The investigation of actinides and

  18. Determination of actinides by alpha spectrometric methods

    The submitted thesis in its first part concern with content determination of plutonium, americium, uranium, thorium radionuclides, like the most significant representatives of actinides in environmental patterns, where by the primary consideration is a focusing on content of these actinides in samples of superior mycotic organisms - mushrooms. Following the published studies the mushrooms were monitored as organisms that could verify most of attributes putted on bioindicators in term of observation of substantial radionuclides in living environment. There were analyzed two groups of samples that came from two chosen locations, one of them is situated in Eastern Slovakia and the second one in West Slovakia. Except for mushrooms samples the examined radionuclides volumes were determined even in specimens of soil sub-base and some plants from chosen localities. The liquid - liquid extraction methods were used for determination of mass activities of actinides in samples for radiochemical separation of monitored radionuclides. The obtained results of plutonium and americium mass activities determination's lead us to carry out experiments that proved abilities of superior mycotic organisms to absorb and accumulate alpha radionuclides in their textures. We choose the oyster mushroom (Pleurotus ostreatus) species as an experimental object. Sporocarps of this mushroom were cultivated on substratum which is commercially exploited to cultivate it whereby this substratum was purposely contaminated by known activities of 239Pu and 241Am. We prepared five autonomous samples together. The values of mass activities of 239Pu and 241Am obtained by following analysis of prepared samples showed the ability of mushrooms to absorb observed actinides in their texture structures. On the basis of obtained mass activities it was possible to evaluate and numerically determine a transmitting factor's attributes of monitored radionuclides in sporocarps and in sub-base. Accordingly we defined

  19. Actinide-only burnup credit for spent fuel transport

    A conservative methodology is described that would allow taking credit for burn up in the criticality safety analysis of spent nuclear fuel packages. Requirements for its implementation include isotopic and criticality validation, generation of package loading criteria using limiting parameters, and assembly burn up verification by measurement. The method allows credit for the changes in the 234U, 235U, 236U, 238U, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, and 241Am concentrations with burnup. No credit for fission product neutron absorbers is taken. Analyses are included regarding the methodology's financial benefits and conservative margin. It is estimated that the proposed actinide-only burnup credit methodology would save 20% of the transport costs. Nevertheless, the methodology includes a substantial margin. Conservatism due to the isotopic correction factors, limiting modelling parameters, limiting axial profiles and exclusion of the fission products ranges from 10 to 25% k. (author)

  20. Optimisation and application of ICP-MS and alpha-spectrometry for determination of isotopic ratios of depleted uranium and plutonium in samples collected in Kosovo

    Boulyga, S. F.; Testa, C; Desideri, D.; Becker, J. S.

    2001-01-01

    The determination of environmental contamination with natural and artificial actinide isotopes and evaluation of their source requires precise isotopic determination of actinides, above all uranium and plutonium. This can be achieved by alpha spectrometry or by inductively coupled plasma mass spectrometry (ICP-MS) after chemical separation of actinides. The performance of a sector-field ICP-MS (ICP-SFMS) coupled to a low-flow micronebulizer with a membrane desolvation unit, "Aridus'', was stu...

  1. The uncertainty analysis of a liquid metal reactor for burning minor actinides from light water reactors

    Choi, Hang Bok [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    The neutronics analysis of a liquid metal reactor for burning minor actinides has shown that uncertainties in the nuclear data of several key minor actinide isotopes can introduce large uncertainties in the predicted performance of the core. A comprehensive sensitivity and uncertainty analysis was performed on a 1200 MWth actinide burner designed for a low burnup reactivity swing, negative doppler coefficient, and low sodium void worth. Sensitivities were generated using depletion perturbation methods for the equilibrium cycle of the reactor and covariance data was taken ENDF-B/V and other published sources. The relative uncertainties in the burnup swing, doppler coefficient, and void worth were conservatively estimated to be 180%, 97%, and 46%, respectively. 5 refs., 1 fig., 3 tabs. (Author)

  2. Standard practice for alternate actinide calibration for inductively coupled plasma-mass spectrometry

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This practice provides guidance for an alternate linear calibration for the determination of selected actinide isotopes in appropriately prepared aqueous solutions by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). This alternate calibration is mass bias adjusted using thorium-232 (232Th) and uranium-238 (238U) standards. One of the benefits of this standard practice is the ability to calibrate for the analysis of highly radioactive actinides using calibration standards at much lower specific activities. Environmental laboratories may find this standard practice useful if facilities are not available to handle the highly radioactive standards of the individual actinides of interest. 1.2 The instrument response for a series of determinations of known concentration of 232Th and 238U defines the mass versus response relationship. For each standard concentration, the slope of the line defined by 232Th and 238U is used to derive linear calibration curves for each mass of interest using interference equ...

  3. Experimental and calculational analyses of actinide samples irradiated in EBR-II

    Higher actinides influence the characteristics of spent and recycled fuel and dominate the long-term hazards of the reactor waste. Reactor irradiation experiments provide useful benchmarks for testing the evaluated nuclear data for these actinides. During 1967 to 1970, several actinide samples were irradiated in the Idaho EBR-II fast reactor. These samples have now been analyzed, employing mass and alpha spectrometry, to determine the heavy element products. A simple spherical model for the EBR-II core and a recent version of the ORIGEN code with ENDF/B-V data were employed to calculate the exposure products. A detailed comparison between the experimental and calculated results has been made. For samples irradiated at locations near the core center, agreement within 10% was obtained for the major isotopes and their first daughters, and within 20% for the nuclides up the chain. A sensitivity analysis showed that the assumed flux should be increased by 10%

  4. Updated multi-group cross sections of minor actinides with improved resonance treatment

    The study of minor actinide in transmutation reactors and other future applications makes resonance self-shielding treatment a significant issue for criticality and isotope depletion. Resonance treatment for minor actinides has been carried out by subgroup method with improved interference effect through interference correction. Subgroup data was generated using RMET21 and GENP codes along with multi-group cross section data by NJOY nuclear data processing system. Updated multi-group cross section data library for a neutron transport code nTRACER was compared with solutions from MCNPX. The resonance interaction of uranium with minor actinides has been included by modified interference treatment of interference correction in subgroup methodology. The comparison of cross sections and multiplication factor in pin and assembly problems showed significant improvement from systematic resonance treatment especially for 237Np and 243Am. (author)

  5. Determination of long-lived actinides in soil leachates by inductively coupled plasma: Mass spectrometry

    Inductively coupled plasma -- mass spectrometry (ICP-MS) was used to concurrently determine multiple long-lived (t1/2 > 104 y) actinide isotopes in soil samples. Ultrasonic nebulization was found to maximize instrument sensitivity. Instrument detection limits for actinides in solution ranged from 50 mBq L-1 (239Pu) to 2 μBq L-1 (235U) Hydride adducts of 232Th and 238U interfered with the determinations of 233U and 239 Pu; thus, extraction chromatography was, used to eliminate the sample matrix, concentrate the analytes, and separate uranium from the other actinides. Alpha spectrometric determinations of 230Th, 239Pu, and the 234U/238U activity ratio in soil leachates compared well with ICP-MS determinations; however, there were some small systematic differences (ca. 10%) between ICP-MS and a-spectrometric determinations of 234U and 238U activities

  6. Methodologies for an improved prediction of the isotopic content in high burnup samples. Application to Vandellós-II reactor core

    Highlights: ► The isotopic prediction of high burnup samples has been addressed through the use of MONTEBURNS 2.0 and SCALE 6.0. ► It is implemented a power normalization capability in MONTEBURNS 2.0 so the user can specify precise experimental powers. ► MONTEBURNS 2.0 has been modified to handle the complete list of isotopes managed by ORIGEN 2.1. ► An external capability is developed to follow irradiations involving geometrical and positional changes automatically. - Abstract: Fuel cycles are designed with the aim of obtaining the highest amount of energy possible. Since higher burnup values are reached, it is necessary to improve our disposal designs, traditionally based on the conservative assumption that they contain fresh fuel. The criticality calculations involved must consider burnup by making the most of the experimental and computational capabilities developed, respectively, to measure and predict the isotopic content of the spent nuclear fuel. These high burnup scenarios encourage a review of the computational tools to find out possible weaknesses in the nuclear data libraries, in the methodologies applied and their applicability range. Experimental measurements of the spent nuclear fuel provide the perfect framework to benchmark the most well-known and established codes, both in the industry and academic research activity. For the present paper, SCALE 6.0/TRITON and MONTEBURNS 2.0 have been chosen to follow the isotopic content of four samples irradiated in the Spanish Vandellós-II pressurized water reactor up to burnup values ranging from 40 GWd/MTU to 75 GWd/MTU. By comparison with the experimental data reported for these samples, we can probe the applicability of these codes to deal with high burnup problems. We have developed new computational tools within MONTENBURNS 2.0. They make possible to handle an irradiation history that includes geometrical and positional changes of the samples within the reactor core. This paper describes the

  7. PWRs potentialities for minor actinides burning

    In the frame of the SPIN program at CEA, the impacts of the minor actinides (MA) incineration in PWRs are analysed. The aim is to reduce the mass, the potential radiotoxicity level. The recycling of all actinide elements is evaluated in a PWR nuclear yard. A sensitivity study is done to evaluate the incineration for each minor actinide element. This gives the most efficient way of incineration for each MA elements in a PWR and helps to design a PWR burner. This burner is disposed in a PWR nuclear system in which the actinides are recycled until equilibrium. (author)

  8. Chemistry of actinides and fission products

    This task is concerned primarily with the fundamental chemistry of the actinide and fission product elements. Special efforts are made to develop research programs in collaboration with researchers at universities and in industry who have need of national laboratory facilities. Specific areas currently under investigation include: (1) spectroscopy and photochemistry of actinides in low-temperature matrices; (2) small-angle scattering studies of hydrous actinide and fission product polymers in aqueous and nonaqueous solvents; (3) kinetic and thermodynamic studies of complexation reactions in aqueous and nonaqueous solutions; and (4) the development of inorganic ion exchange materials for actinide and lanthanide separations. Recent results from work in these areas are summarized here

  9. Long-term plant availability of actinides

    Environmental releases of actinide elements raise issues about which data are very limited. Quantitative information is required to assess the long-term behavior of actinides and their potential hazards resulting from the transport through food chains leading to man. Of special interest is the effect of time on the changes in the availability of actinide elements for uptake by plants from soil. This study provides valuable information on the effects of weathering and aging on the uptake of actinides from soil by range and crop plants grown under realistic field conditions

  10. A measurement of actinide neutron transmutations with accelerator mass spectrometry in order to infer neutron capture cross sections

    Bauder, William K.

    Improved neutron capture cross section data for transuranic and minor actinides are essential for assessing possibilities for next generation reactors and advanced fuel cycles. The Measurement of Actinide Neutron TRAnsmutation (MANTRA) project aims to make a comprehensive set of energy integrated neutron capture cross section measurements for all relevant isotopes from Th to Cf. The ability to extract these cross sections relies on the use of Accelerator Mass Spectrometry (AMS) to analyze isotopic concentrations in samples irradiated in the Advanced Test Reactor (ATR). The AMS measurements were performed at the Argonne Tandem Linear Accelerator System (ATLAS) and required a number of key technical developments to the ion source, accelerator, and detector setup. In particular, a laser ablation material injection system was developed at the electron cyclotron resonance ion source. This system provides a more effective method to produce ion beams from samples containing only 1% actinide material and offers some benefits for reducing cross talk in the source. A series of four actinide measurements are described in this dissertation. These measurements represent the most substantial AMS work attempted at ATLAS and the first results of the MANTRA project. Isotopic ratios for one and two neutron captures were measured in each sample with total uncertainties around 10%. These results can be combined with a MCNP model for the neutron fluence to infer actinide neutron capture cross sections.

  11. Mass spectrometric method for the determination of the stable isotopic content of nitrous oxide by the technique of direct injection

    A method for the direct isotopic analysis of N2O has been developed for VG-Prism H dynamic dual inlet stable isotope mass spectrometer. Tests have shown extreme sensitivity to contamination by carbon dioxide with a dependence of 6.8 per mille per % CO2 for δ15N and 12.4 per mille per % CO2 for δ18O. Trace amounts of CO2 have proven difficult to eliminate, particularly for small sample sizes. In order to ensure accurate analyses an indicator of CO2 contamination must be monitored and corrections applied when necessary. We have found that ions with mass to charge ratios of 12 and 22 are excellent proxies for CO2 contamination. Empirical relationships between these indicator species and CO2 contamination are documented which allow for corrections to be applied to raw data. Additional corrections required due to the presence of isobaric molecules containing 17O are described. Issues of standardization are discussed and sample handling procedures described. Finally, these methods and corrections are applied to a suite of stratospheric air samples. (author)

  12. Trace analysis of actinides in the environment using resonance ionization mass spectrometry

    In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 104-105 atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope 236U a detection limit down to 10-9 for the isotope ratio N (236U)/N (238U) could be determined.

  13. Comparative analysis between measured and calculated concentrations of major actinides using destructive assay data from Ohi-2 PWR

    Oettingen Mikołaj

    2015-09-01

    Full Text Available In the paper, we assess the accuracy of the Monte Carlo continuous energy burnup code (MCB in predicting final concentrations of major actinides in the spent nuclear fuel from commercial PWR. The Ohi-2 PWR irradiation experiment was chosen for the numerical reconstruction due to the availability of the final concentrations for eleven major actinides including five uranium isotopes (U-232, U-234, U-235, U-236, U-238 and six plutonium isotopes (Pu-236, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242. The main results were presented as a calculated-to-experimental ratio (C/E for measured and calculated final actinide concentrations. The good agreement in the range of ±5% was obtained for 78% C/E factors (43 out of 55. The MCB modeling shows significant improvement compared with the results of previous studies conducted on the Ohi-2 experiment, which proves the reliability and accuracy of the developed methodology.

  14. Plutonium and minor actinide utilisation in a pebble-bed high temperature reactor

    This paper contains results of the analysis of the pebble-bed high temperature gas-cooled PUMA reactor loaded with plutonium and minor actinide (Pu/MA) fuel. Starting from knowledge and experience gained in the Euratom FP5 projects HTR-N and HTR-N1, this study aims at demonstrating the potential of high temperature reactors to utilize or transmute Pu/MA fuel. The work has been performed within the Euratom FP6 project PUMA. A number of different fuel types and fuel configurations have been analyzed and compared with respect to incineration performance and safety-related reactor parameters. The results show the excellent plutonium and minor actinide burning capabilities of the high temperature reactor. The largest degree of incineration is attained in the case of an HTR fuelled by pure plutonium fuel as it remains critical at very deep burnup of the discharged pebbles. Addition of minor actinides to the fuel leads to decrease of the achievable discharge burnup and therefore smaller fraction of actinides incinerated during reactor operation. The inert-matrix fuel design improves the transmutation performance of the reactor, while the 'wallpaper' fuel does not have advantage over the standard fuel design in this respect. After 100 years of decay following the fuel discharge, the total amount of actinides remains almost unchanged for all of the fuel types considered. Among the plutonium isotopes, only the amount of Pu-241 is reduced significantly due to its relatively short half-life. (authors)

  15. Plutonium and minor actinide utilisation in a pebble-bed high temperature reactor

    Petrov, B. Y.; Kuijper, J. C.; Oppe, J.; De Haas, J. B. M. [Nuclear Research and Consultancy Group, Westerduinweg 3, 1755 ZG Petten (Netherlands)

    2012-07-01

    This paper contains results of the analysis of the pebble-bed high temperature gas-cooled PUMA reactor loaded with plutonium and minor actinide (Pu/MA) fuel. Starting from knowledge and experience gained in the Euratom FP5 projects HTR-N and HTR-N1, this study aims at demonstrating the potential of high temperature reactors to utilize or transmute Pu/MA fuel. The work has been performed within the Euratom FP6 project PUMA. A number of different fuel types and fuel configurations have been analyzed and compared with respect to incineration performance and safety-related reactor parameters. The results show the excellent plutonium and minor actinide burning capabilities of the high temperature reactor. The largest degree of incineration is attained in the case of an HTR fuelled by pure plutonium fuel as it remains critical at very deep burnup of the discharged pebbles. Addition of minor actinides to the fuel leads to decrease of the achievable discharge burnup and therefore smaller fraction of actinides incinerated during reactor operation. The inert-matrix fuel design improves the transmutation performance of the reactor, while the 'wallpaper' fuel does not have advantage over the standard fuel design in this respect. After 100 years of decay following the fuel discharge, the total amount of actinides remains almost unchanged for all of the fuel types considered. Among the plutonium isotopes, only the amount of Pu-241 is reduced significantly due to its relatively short half-life. (authors)

  16. Gas core reactors for actinide transmutation and breeder applications. Annual report

    This work consists of design power plant studies for four types of reactor systems: uranium plasma core breeder, uranium plasma core actinide transmuter, UF6 breeder and UF6 actinide transmuter. The plasma core systems can be coupled to MHD generators to obtain high efficiency electrical power generation. A 1074 MWt UF6 breeder reactor was designed with a breeding ratio of 1.002 to guard against diversion of fuel. Using molten salt technology and a superheated steam cycle, an efficiency of 39.2% was obtained for the plant and the U233 inventory in the core and heat exchangers was limited to 105 Kg. It was found that the UF6 reactor can produce high fluxes (10 to the 14th power n/sq cm-sec) necessary for efficient burnup of actinide. However, the buildup of fissile isotopes posed severe heat transfer problems. Therefore, the flux in the actinide region must be decreased with time. Consequently, only beginning-of-life conditions were considered for the power plant design. A 577 MWt UF6 actinide transmutation reactor power plant was designed to operate with 39.3% efficiency and 102 Kg of U233 in the core and heat exchanger for beginning-of-life conditions

  17. Foraging ecology of ringed seals (Pusa hispida, beluga whales (Delphinapterus leucas and narwhals (Monodon monoceros in the Canadian High Arctic determined by stomach content and stable isotope analysis

    Jordan K. Matley

    2015-05-01

    Full Text Available Stomach content and stable isotope analysis (δ13C and δ15N from liver and muscle were used to identify habitat and seasonal prey selection by ringed seals (Pusa hispida; n=21, beluga whales (Delphinapterus leucas; n=13 and narwhals (Monodon monoceros; n=3 in the eastern Canadian Arctic. Arctic cod (Boreogadus saida was the main prey item of all three species. Diet reconstruction from otoliths and stable isotope analysis revealed that while ringed seal size influenced prey selection patterns, it was variable. Prey-size selection and on-site observations found that ringed seals foraged on smaller, non-schooling cod whereas belugas and narwhals consumed larger individuals in schools. Further interspecific differences were demonstrated by δ13C and δ15N values and indicated that ringed seals consumed inshore Arctic cod compared to belugas and narwhals, which foraged to a greater extent offshore. This study investigated habitat variability and interseasonal variation in the diet of Arctic marine mammals at a local scale and adds to the sparse data sets available in the Arctic. Overall, these findings further demonstrate the critical importance of Arctic cod to Arctic food webs.

  18. Mineralogy of diamonds from the Juina Kimberlite Province, SW Amazon Craton, Brazil: cathodoluminescence, infrared spectroscopy, nitrogen content, and carbon and nitrogen isotopes

    The mineralogy of 234 primary and alluvial diamonds from the Juina kimberlite Province has been investigated. The majority of diamonds exhibit low CL intensity and typical blue-sky color. Internal features are rare. The spectra classification of diamonds yields 82% of Type II stones (N-free and a minor amount of highly aggregated Type I diamonds. δ13C in Type II diamonds varies from - 3 to - 26.3% and in Type I from -3.4% - 13.8%. δ15 N in Type I diamonds ranges from +2.2 to - 14.0% and the N content, from 3.85 to 613.74 at.ppm. C and N isotopic compositions are compared to worldwide occurrences and to deep diamond assemblages. The incorporation of N by deep diamonds and the contribution of subducted terrains of the SW border of the Amazon Craton on the formation of the light 13 C diamonds are briefly discussed. (author)

  19. MANTRA: Measuring Neutron Capture Cross Sections in Actinides with Accelerator Mass Spectrometry

    Bauder, W.; Pardo, R. C.; Collon, P.; Palchan, T.; Scott, R.; Vondrasek, R.; Nusair, O.; Nair, C.; Paul, M.; Kondev, F.; Chen, J.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2013-10-01

    With rising global energy needs, there is substantial interest in nuclear energy research. To explore possibilities for advanced fuel cycles, better neutron cross section data are needed for the minor actinides. The MANTRA (Measurement of Actinide Neutron TRAsmutation) project will improve these data by measuring integral (n, γ) cross sections. The cross sections will be extracted by measuring isotopic ratios in pure actinide samples, irradiated in the Advanced Test Reactor at Idaho National Lab, using Accelerator Mass Spectrometry(AMS) at the Argonne Tandem Linac Accelerator System (ATLAS). MANTRA presents a unique AMS challenge because of the goal to measure multiple isotopic ratios on a large number of samples. To meet these challenges, we have modified the AMS setup at ATLAS to include a laser ablation system for solid material injection into our ECR ion source. I will present work on the laser ablation system and modified source geometry, as well as preliminary measurements of unirradiated actinide samples at ATLAS. This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

  20. Calculated Atomic Volumes of the Actinide Metals

    Skriver, H.; Andersen, O. K.; Johansson, B.

    1979-01-01

    The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium.......The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium....

  1. Environmental chemistry of the actinide elements

    The environmental chemistry of the actinide elements is a new branch of science developing with the application of nuclear energy on a larger and larger scale. Various aspects of the environmental chemistry of the actinide elements are briefly reviewed in this paper, such as its significance in the nuclear waste disposal, its coverage of research fields and possible directions for future study

  2. PIE analysis for minor actinide

    Minor actinide (MA) is generated in nuclear fuel during the operation of power reactor. For fuel design, reactivity decrease due to it should be considered. Out of reactors, MA plays key role to define the property of spent fuel (SF) such as α-radioactivity, neutron emission rate, and criticality of SF. In order to evaluate the calculation codes and libraries for predicting the amount of MA, comparison between calculation results and experimentally obtained data has been conducted. In this report, we will present the status of PIE data of MA taken by post irradiation examinations (PIE) and several calculation results. (author)

  3. Heavy coolant fast neutron reactor BRUS-150 for minor actinides burning and U-233 build-up

    The present paper deals with the calculational research into the performance of fast reactor BRUS-150 cooled with liquid metal coolant eutectic lead-bismuth alloy with reference to minor actinides (Np, Am, Cm) transmutation and isotopic pure U 233 build up. (authors). 10 refs., 2 figs

  4. Actinide co-conversion by internal gelation

    Suitable microstructures and homogenous microspheres of actinide compounds are of interest for future nuclear fuel or transmutation target concepts to prevent the generation and dispersal of actinide powder. Sol-gel routes are being investigated as one of the possible solutions for producing these compounds. Preliminary work is described involving internal gelation to synthesize mixed compounds including minor actinides, particularly mixed actinide or mixed actinide-inert element compounds. A parameter study is discussed to highlight the importance of the initial broth composition for obtaining gel microspheres without major defects (cracks, craters, etc.). In particular, conditions are defined to produce gel beads from Zr(IV)/Y(III)/Ce(III) or Zr(IV)/An(III) systems. After gelation, the heat treatment of these microspheres is described for the purpose of better understanding the formation of cracks after calcination and verifying the effective synthesis of an oxide solid-solution. (authors)

  5. Actinide ion sensor for pyroprocess monitoring

    Jue, Jan-fong; Li, Shelly X.

    2014-06-03

    An apparatus for real-time, in-situ monitoring of actinide ion concentrations which comprises a working electrode, a reference electrode, a container, a working electrolyte, a separator, a reference electrolyte, and a voltmeter. The container holds the working electrolyte. The voltmeter is electrically connected to the working electrode and the reference electrode and measures the voltage between those electrodes. The working electrode contacts the working electrolyte. The working electrolyte comprises an actinide ion of interest. The reference electrode contacts the reference electrolyte. The reference electrolyte is separated from the working electrolyte by the separator. The separator contacts both the working electrolyte and the reference electrolyte. The separator is ionically conductive to the actinide ion of interest. The reference electrolyte comprises a known concentration of the actinide ion of interest. The separator comprises a beta double prime alumina exchanged with the actinide ion of interest.

  6. Sympathetic re-innervation after heart transplantation: dual-isotope neurotransmitter scintigraphy, norepinephrine content and historical examination

    Cardiac transplantation entails surgical disruption of the sympathetic nerve fibres from their somata, resulting in sympathetic denervation. In order to investigate the occurrence of sympathetic re-innervation, neurotransmitter scintigraphy using the norepinephrine analogue iodine-123 metaiodobenzylguanidine (MIBG) was performed in 15 patients 2-69 months after transplantation. In addition, norepinephrine content and immunohistochemical reactions of antibodies to Schwann cell-associated S100 protein, to neuron-specific enolase (NSE) and to norepinephrine were examined in 34 endomyocardial biopsies of 29 patients 1-88 months after transplantation. Anterobasal 123I-MIBG uptake indicating partial sympathetic re-innervation could be shown in 40% of the scintigraphically investigated patients 37-69 months after transplantation. In immunohistochemical studies 83% of the patients investigated 1-72 Months after transplantation showed nerve fibres in their biopsies but not positive reaction to norepinephrine. Significant norepinephrine content indicating re-innervation could not be detected in any biopsy. It was concluded that in spite of the lack of norepinephrine content there seemed to be immunohistological and scintigraphic evidence of sympathetic re-innervation. An explanation for this contradictory finding may be the reduced or missing norepinephrine storage ability compared to the restored uptake ability of regenerated sympathetic nerve fibres. (orig.)

  7. The ALMR actinide burning system

    The advanced liquid-metal reactor (ALMR) actinide burning system is being developed under the sponsorship of the US Department of Energy to bring its unique capabilities to fruition for deployment in the early 21st century. The system consists of four major parts: the reactor plant, the metal fuel and its recycle, the processing of light water reactor (LWR) spent fuel to extract the actinides, and the development of a residual waste package. This paper addresses the status and outlook for each of these four major elements. The ALMR is being developed by an industrial group under the leadership of General Electric (GE) in a cost-sharing arrangement with the US Department of Energy. This effort is nearing completion of the advanced conceptual design phase and will enter the preliminary design phase in 1994. The innovative modular reactor design stresses simplicity, economics, reliability, and availability. The design has evolved from GE's PRISM design initiative and has progressed to the final stages of a prelicensing review by the US Nuclear Regulatory Commission (NRC); a safety evaluation report is expected by the end of 1993. All the major issues identified during this review process have been technically resolved. The next design phases will focus on implementation of the basic safety philosophy of passive shutdown to a safe, stable condition, even without scram, and passive decay heat removal. Economic projections to date show that it will be competitive with non- nuclear and advanced LWR nuclear alternatives

  8. Estimating Change in Sedimentary Organic Carbon Content During Mangrove Restoration in Southern China Using Carbon Isotopic Measurements

    ZHANG Jin-Ping; SHEN Cheng-De; REN Hai; WANG Jun; HAN Wei-Dong

    2012-01-01

    Based on total carbon (C) and C isotopes in sediment cores,sedimentary organic carbon (SOC) was quantified in three types of mangrove sites (barren fiat sites without mangroves,mangrove plantations,and natural mangrove forests),which were considered to represent a continuum from least restored to most restored sites in southern China.SOC densities in the barren sites,plantations,and natural forests were 90,170 and 288 Mg ha-1,respectively.We inferred that mangrove restoration increased SOC accumulation in coastal areas.At 0-70 cm depth,SOC δ13C values in both mangrove sites ranged from -27.37‰ to -23.07‰ and exhibited gradual enrichment with depth.In contrast,the values in the barren flat sites remained around -22.19‰ and fluctuated slightly with depth.At 0-60 cm,the 14C ages of the SOC in the barren flat site,the natural mangrove site,and the artificial mangrove site ranged from 1397 to 2 608,255 to 2 453,and 391 to 2512 years BP,respectively.In both types of mangrove sites but not in the barren flat sites,the enrichment of δ13C with depth was related to increases in SOC decay and SOC age with depth.According to analysis of 14C age,much of the mangrove-derived C was transported and stored at 0-60 cm depth under anaerobic conditions in both mangrove sites.The sediments of mangrove forests in southern China sequester large quantities of SOC during mangrove restoration.

  9. Application of tritium content isotopic measurements to the investigation of underground water circulations and mixing in different porous media

    This research thesis aims at investigating actual and potential mixing of underground waters in different soil types, and more particularly different porous media. Tritium content measurements of these waters have been performed by liquid scintillation after enrichment. The first part of this report addresses the physical aspect of these measurements. The second one deals with the interpretation of the acquired data, of circulation or mixing schemes which can be deduced with respect to the concerned soils. It highlights the importance of geo-morphological factors for the studied flows

  10. Chemical composition, hydrogen and oxygen isotope ratios and tritium content of hot waters and steam condensates from the Oyasu-Doroyu-Akinomiya geothermal area in Akita prefecturs, Japan

    The major and minor chemical components, hydrogen and oxygen isotope ratios and tritium content of river, cold spring and hot spring waters and fumarolic condensates in the Oyasu-Doroyu-Akinomiya geothermal area were analyzed. The hot water and steam condensate blown off from explorative wells and the hot waters collected from different depth of a bore in the Oyasu area were also analyzed. The hot springs and fumaroles in this area erupt mostly from Neogene system, and are distributed predominantly in the NE-SW direction regionally but in the NW-SE direction locally. The acidic Cl- and (SO4)2- types of hot spring water show distinct oxygen shift accompanied by hydrogen shift, but the neutral Na+.Cl- type of hot spring water and the hot water from geothermal wells hardly showed the oxygen shift as compared with the river and cold spring waters. The tritium content of hot water is relatively high in case of the acidic Cl- and (SO4)2- types, but in case of the neutral Na+.Cl- type, it did not exceed 1T.U., and the origin of the water is supposed to be precipitation of probably more than thirty years ago. (Kobatake, H.)

  11. Fabrication of fuel and recycling of minor actinides in fast reactors

    Somers, Joseph

    2010-01-01

    Fuels for future fast reactors will not only produce energy, but they must also actively contribute to the minimisation of long lived wastes produced by these, and other reactor systems. The fuels must incorporate minor actinides (MA = Np, Am, Cm) for neutron transmutation into short lived isotopes. Within Europe oxide fuels are favoured. Transmutation can be considered in homogeneous or heterogeneous reactor recycle modes (i.e. in fuels or targets, respectively). Fabrication of such fuels...

  12. Advanced processes for minor actinides recycling: studies towards potential industrialization

    In June 2006, a new act on sustainable management of radioactive waste was voted by the French parliament with a national plan on radioactive materials and radioactive waste management (PNG-MDR). Concerning partitioning and transmutation, the program is connected to 4. generation reactors, in which transmutation of minor actinides could be operated. In this frame, the next important milestone is 2012, with the assessment of the possible transmutation roads, which are either homogeneous recycling of the minor actinides in the whole reactor fleet, with a low content of M.A (∼3%) in all fuel assemblies, or heterogeneous recycling of the minor actinides in about one third of the reactor park, with a higher content of M.A. (∼20%) in dedicated targets dispatched in the periphery of the reactor. Advanced processes for the recycling of minor actinides are being developed to address the challenges of these various management options. An important part of the program consists in getting closer to process implementation conditions. The processes based on liquid-liquid extraction benefit from the experience gained by operating the PUREX process at the La Hague plant. In the field of extracting apparatus, a large experience is available. In the field of extracting apparatus, a large experience is already available. Nevertheless, the processes present specificities which have to be considered more precisely. They have been classified in the following fields: - Evolution of the simulation codes, including phenomenological representations: with such a simulation tool, it will be possible to assess operating tolerances, lead sensitivity studies and calculate transient states; - Definition of the implementation conditions in continuous contactors (such as pulse columns), according to the extractant physico-chemical characteristics; - Scale-up of new extractants, such as malonamides used in the DIAMEX process, facing purity specifications and costs estimation; - Solvent clean

  13. Characterization of actinide physics specimens for the US/UK joint experiment in the Dounreay Prototype Fast Reactor

    The United States and the United Kingdom are engaged in a joint research program in which samples of the higher actinides are irradiated in the Dounreay Prototype Fast Reactor in Scotland. The purpose of the porogram is (1) to study the materials behavior of selected higher actinide fuels and (2) to determine the integral cross sections of a wide variety of the higher actinide isotopes. Samples of the actinides are incorporated in fuel pins inserted in the core. For the fuel study, the actinides selected are 241Am and 244Cm in the form of Am2O3, Cm2O3, and Am6Cm(RE)7O21, where (RE) represents a mixture of lanthanides. For the cross-section determinations, the samples are milligram quantities of actinide oxides of 248Cm, 246Cm, 244Cm, 243Cm, 243Am, 241Am, 244Pu, 242Pu, 241Pu, 240Pu, 239Pu, 238Pu, 237Np, 238U, 236U, 235U, 234U, 233U, 232Th, 230Th, and 231Pa encapsulated in vanadium. Coincident with the irradiations, neutron flux and energy spectral measurements are made with vanadium-encapsulated dosimeter materials located within the same fuel pins

  14. Use of high gradient magnetic separation for actinide application

    Decontamination of materials such as soils or waste water that contain radioactive isotopes, heavy metals, or hazardous components is a subject of great interest. Magnetic separation is a physical separation process that segregates materials on the basis of magnetic susceptibility. Because the process relies on physical properties, separations can be achieved while producing a minimum of secondary waste. Most traditional physical separation processes effectively treat particles larger than 70 microns. In many situations, the radioactive contaminants are found concentrated in the fine particle size fraction of less than 20 microns. For effective decontamination of the fine particle size fraction most current operations resort to chemical dissolution methods for treatment. High gradient magnetic separation (HGMS) is able to effectively treat particles from 90 to ∼0.1 micron in diameter. The technology is currently used on the 60 ton per hour scale in the kaolin clay industry. When the field gradient is of sufficiently high intensity, paramagnetic particles can be physically captured and separated from extraneous nonmagnetic material. Because all actinide compounds are paramagnetic, magnetic separation of actinide containing mixtures is feasible. The advent of reliable superconducting magnets also makes magnetic separation of weakly paramagnetic species attractive. HGMS work at Los Alamos National Laboratory (LANL) is being developed for soil remediation, waste water treatment and treatment of actinide chemical processing residues. LANL and Lockheed Environmental Systems and Technologies Company (LESAT) have worked on a co-operative research and development agreement (CRADA) to develop HGMS for radioactive soil decontamination. The program is designed to transfer HGMS from the laboratory and other industries for the commercial treatment of radioactive contaminated materials. 9 refs., 2 figs., 2 tabs

  15. Final Report on Actinide Glass Scintillators for Fast Neutron Detection

    Bliss, Mary; Stave, Jean A.

    2012-10-01

    This is the final report of an experimental investigation of actinide glass scintillators for fast-neutron detection. It covers work performed during FY2012. This supplements a previous report, PNNL-20854 “Initial Characterization of Thorium-loaded Glasses for Fast Neutron Detection” (October 2011). The work in FY2012 was done with funding remaining from FY2011. As noted in PNNL-20854, the glasses tested prior to July 2011 were erroneously identified as scintillators. The decision was then made to start from “scratch” with a literature survey and some test melts with a non-radioactive glass composition that could later be fabricated with select actinides, most likely thorium. The normal stand-in for thorium in radioactive waste glasses is cerium in the same oxidation state. Since cerium in the 3+ state is used as the light emitter in many scintillating glasses, the next most common substitute was used: hafnium. Three hafnium glasses were melted. Two melts were colored amber and a third was clear. It barely scintillated when exposed to alpha particles. The uses and applications for a scintillating fast neutron detector are important enough that the search for such a material should not be totally abandoned. This current effort focused on actinides that have very high neutron capture energy releases but low neutron capture cross sections. This results in very long counting times and poor signal to noise when working with sealed sources. These materials are best for high flux applications and access to neutron generators or reactors would enable better test scenarios. The total energy of the neutron capture reaction is not the only factor to focus on in isotope selection. Many neutron capture reactions result in energetic gamma rays that require large volumes or high densities to detect. If the scintillator is to separate neutrons from gamma rays, the capture reactions should produce heavy particles and few gamma rays. This would improve the detection of a

  16. Experimental studies of actinides in molten salts

    Reavis, J.G.

    1985-06-01

    This review stresses techniques used in studies of molten salts containing multigram amounts of actinides exhibiting intense alpha activity but little or no penetrating gamma radiation. The preponderance of studies have used halides because oxygen-containing actinide compounds (other than oxides) are generally unstable at high temperatures. Topics discussed here include special enclosures, materials problems, preparation and purification of actinide elements and compounds, and measurements of various properties of the molten volts. Property measurements discussed are phase relationships, vapor pressure, density, viscosity, absorption spectra, electromotive force, and conductance. 188 refs., 17 figs., 6 tabs.

  17. Electronic structure and magnetic properties of actinides

    The study of the actinide series shows the change between transition metal behavior and lanthanide behavior, between constant weak paramagnetism for thorium and strong Curie-Weiss paramagnetism for curium. Curium is shown to be the first metal of the actinide series to be magnetically ordered, its Neel temperature being 52K. The magnetic properties of the actinides depending on all the peripheral electrons, their electronic structure was studied and an attempt was made to determine it by means of a phenomenological model. Attempts were also made to interrelate the different physical properties which depend on the outer electronic structure

  18. Actinide chemistry in the far field

    The environmental chemistry of the actinides is complicated due both to the extensive redox and coordination chemistry of the elements and also to the complexity of the reactive phases encountered in natural environments. In the far field, interactions with reactive surfaces, coatings and colloidal particles will play a crucial role in controlling actinide mobility. By virtue of both their abundance and reactivity; clays and other layer aluminosilicate minerals, hydrous oxides and organic matter (humic substances) are all identified as having the potential to react with actinide ions and some possible modes of interaction are described, together with experimental evidence for their occurrence. (author)

  19. Experimental studies of actinides in molten salts

    This review stresses techniques used in studies of molten salts containing multigram amounts of actinides exhibiting intense alpha activity but little or no penetrating gamma radiation. The preponderance of studies have used halides because oxygen-containing actinide compounds (other than oxides) are generally unstable at high temperatures. Topics discussed here include special enclosures, materials problems, preparation and purification of actinide elements and compounds, and measurements of various properties of the molten volts. Property measurements discussed are phase relationships, vapor pressure, density, viscosity, absorption spectra, electromotive force, and conductance. 188 refs., 17 figs., 6 tabs

  20. Spin and orbital moments in actinide compounds

    Lebech, B.; Wulff, M.; Lander, G.H.

    1991-01-01

    -electron band-structure calculations, is that the orbital moments of the actinide 5f electrons are considerably reduced from the values anticipated by a simple application of Hund's rules. To test these ideas, and thus to obtain a measure of the hybridization, we have performed a series of neutron scattering...... experiments designed to determine the magnetic moments at the actinide and transition-metal sublattice sites in compounds such as UFe2, NpCo2, and PuFe2 and to separate the spin and orbital components at the actinide sites. The results show, indeed, that the ratio of the orbital to spin moment is reduced as...

  1. Endohedral Fullerenes with Actinide-Actinide Bonds: Unwilling Bonding in U2@C80

    Foroutan-Nejad, C.; Patzschke, M.; Straka, Michal

    Opole: -, 2014. [MMNB 2014. Polish-Taiwanese Conference. From Molecular Modeling to Nano- and Biotechnology . 04.09.2014-06.09.2014, Opole] R&D Projects: GA ČR(CZ) GA14-03564S Grant ostatní: European Social Fund(XE) CZ.1.07/2.3.00/30.009 Institutional support: RVO:61388963 Keywords : endohedral actinide fullerene * U-U bonding * actinide-actinide bonding Subject RIV: CF - Physical ; Theoretical Chemistry

  2. Criticality analysis of aggregations of actinides from commerical nuclear waste in geological storage

    An underground nuclear-waste terminal-storage facility for either spent fuel elements or high level waste from a reprocessing plant will contain large amounts of fissionable actinides. Such a facility must be designed to preclude the concentration of these isotopes into a critical mass. Information on the critical masses of the various isotopes present in spent fuel or high level waste is required as part of such a design effort. This study provides this information. The results of this study will be used, in conjunction with geologic transport rates of the actinide compounds, to estimate mass formation probabilities in waste repositories. A computational model was developed as part of the study to perform criticality calculations rapidly and efficiently and to produce tables and plots of actinide concentration in geologic material versus critical mass. The criticality model uses a discrete ordinates approximation to neutron transport theory and treats six energy groups and spherical geometry. Neutron cross sections were obtained from ENDF/B-IV or ENDF/B-V cross section libraries. Critical masses calculated with the computational model were checked against experimental values and against more detailed calculational values and were found to be from 30 percent less to 10 percent greater. Critical mass calculations were made for five waste types, five waste ages, five actinide elements, and four geologic compositions. Minimum critical masses were calculated for over 400 combinations of the above variables. The relative importance for criticality of the various actinides and waste types is presented in terms of the number of possible critical masses per waste container

  3. Actinide recovery from pyrochemical residues

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 62- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO3-4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  4. Determination of artifactual formation of monomethylmercury (CH{sub 3}Hg{sup +}) in environmental samples using stable Hg{sup 2+} isotopes with ICP-MS detection: Calculation of contents applying species specific isotope addition

    Hintelmann, H. [Trent University, Environmental Science Centre, Peterborough ON K9J 7B8 (Canada); Falter, R. [Bayreuth Institute for Terrestrial Ecosystem Research (BITOEK), Central Analytics, POB 101251, University of Bayreuth, D-95440 Bayreuth (Germany); Ilgen, G. [Bayreuth Institute for Terrestrial Ecosystem Research (BITOEK), Central Analytics, POB 101251, University of Bayreuth, D-95440 Bayreuth (Germany); Evans, R.D. [Trent University, Environmental Science Centre, Peterborough ON K9J 7B8 (Canada)

    1997-06-01

    Various extraction techniques, as distillation, acid and alkaline extraction, have been tested with regard to their potential to form a monomethylmercury (CH{sub 3}Hg{sup +}) artifact from inorganic Hg during sample preparation. Hg{sup 2+} has been added to different reference materials in the form of enriched stable tracers and the formation of new methylmercury from that tracer has been analyzed by HPLC/ICP-MS and GC/ICP-MS. Both techniques gave comparable results. In particular, the distillation technique was prone to artifact formation. The resulting overestimation of methylmercury in sediments was as high as 80%. Artifact formation in hair, liver and algae samples was less significant, though still observable. Fish muscle tissue showed no artifact formation upon distillation, but some of the inorganic tracer was converted to methylmercury during alkaline extraction. Acid extraction of sediments resulted in low artifact formation rates. Fractionated measurements of sediment distillates revealed high methylmercury formation rates towards the end of the distillation process when acid concentrations in the solution are highest. A technique for correction of the measured apparent methylmercury content applying species specific isotope addition (SSIA) is proposed and the calculation scheme is presented. (orig.). With 6 figs., 3 tabs.

  5. HTGR actinide burner feasibility studies: Calculation scheme related considerations

    At the CEA, the actinides burner version of the prismatic block-type reactor is currently investigated, including studies about the design proposed by General Atomics. The purpose of this paper is essentially to evaluate the capability of the deterministic methods to calculate a wide range of core configurations. In the first part of the paper, the analysis is carried out on the 'Deep Burner' fuel element geometry. The fuel element calculations are performed with both Transport code APOLLO2 and Monte-Carlo code TRIPOLI4. This preliminary analysis shows the reliability of the deterministic code APOLLO2 to calculate heterogeneous fuel element configurations (fuel element loaded with plutonium and minor actinides). In the second part, the analysis deals with the core geometry in order to estimate the impact of some physical assumptions on the fine fuel isotopic depletion. Due to the strong spectrum transient in the core, it turns out that the transuranic mass balances in a GT-MHR cannot be estimated easily from fuel element calculations but rather need the use of a core modeling approach taking into account the presence of the graphite reflectors. Two different methods based on a fine core Diffusion calculation in CRONOS2 and a simplified Transport calculation in APOLLO2 are investigated in this paper. (authors)

  6. Multi-nucleon transfer experiments in the actinide region

    Geibel, Kerstin; Reiter, Peter; Birkenbach, Benedikt [Institut fuer Kernphysik, Universitaet zu Koeln (Germany); Valiente-Dobon, Jose Javier; Recchia, Francesco [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (Italy); Gadea, Andres [IFIC, CSIC-Universidad de Valencia (Spain); Lenzi, Silvia [Dipartimento di Fisica, University of Padova (Italy)

    2012-07-01

    Two experiments at the PRISMA-CLARA-Setup at the LNL in Legnaro were analysed focussing on the target-like reaction products in the actinide region after multi-nucleon transfer reactions. Both experiments use {sup 238}U as target; a {sup 70}Zn-beam with 460 MeV and a {sup 136}Xe-beam with 926 MeV were employed. Kinematic correlations between the reaction partners are used to obtain information about the unobserved target-like reaction products by the analysis of the beam-like particles identified with the PRISMA-spectrometer. Clean {gamma}-spectra from neutron-rich actinide nuclei are obtained with the CLARA-array. An extension of the ground state rotational band in {sup 240}U and insights in neutron-rich Th-isotopes were achieved. Based on relative cross section distributions for various reaction channels the perspectives and limitations for in-beam {gamma}-spectroscopy with this experimental method in this mass region are discussed.

  7. Subsurface interactions of actinide species and microorganisms. Implications for the bioremediation of actinide-organic mixtures

    By reviewing how microorganisms interact with actinides in subsurface environments, the way how bioremediation controls the fate of actinides is assessed. Actinides often are co-contaminants with strong organic chelators, chlorinated solvents, and fuel hydrocarbons. Bioremediation can immobilize the actinides, biodegrade the co-contaminants, or both. Actinides at the IV oxidation state are the least soluble, and microorganisms accelerate precipitation by altering the actinide's oxidation state or its speciation. The way how microorganisms directly oxidize or reduce actinides and how microbiological reactions that biodegrade strong organic chelators, alter the pH, and consume or produce precipitating anions strongly affect actinide speciation and, therefore, mobility is described. Why inhibition caused by chemical or radiolytic toxicities uniquely affects microbial reactions is explained. Due to the complex interactions of the microbiological and chemical phenomena, mathematical modeling is an essential tool for research on and application of bioremediation involving co-contamination with actinides. Development of mathematical models that link microbiological and geochemical reactions is described. Throughout, the key research needs are identified. (author)

  8. Subsurface interactions of actinide species and microorganisms : implications for the bioremediation of actinide-organic mixtures.

    Banaszak, J.E.; Reed, D.T.; Rittmann, B.E.

    1999-02-12

    By reviewing how microorganisms interact with actinides in subsurface environments, we assess how bioremediation controls the fate of actinides. Actinides often are co-contaminants with strong organic chelators, chlorinated solvents, and fuel hydrocarbons. Bioremediation can immobilize the actinides, biodegrade the co-contaminants, or both. Actinides at the IV oxidation state are the least soluble, and microorganisms accelerate precipitation by altering the actinide's oxidation state or its speciation. We describe how microorganisms directly oxidize or reduce actinides and how microbiological reactions that biodegrade strong organic chelators, alter the pH, and consume or produce precipitating anions strongly affect actinide speciation and, therefore, mobility. We explain why inhibition caused by chemical or radiolytic toxicities uniquely affects microbial reactions. Due to the complex interactions of the microbiological and chemical phenomena, mathematical modeling is an essential tool for research on and application of bioremediation involving co-contamination with actinides. We describe the development of mathematical models that link microbiological and geochemical reactions. Throughout, we identify the key research needs.

  9. Subsurface interactions of actinide species and microorganisms : implications for the bioremediation of actinide-organic mixtures

    By reviewing how microorganisms interact with actinides in subsurface environments, we assess how bioremediation controls the fate of actinides. Actinides often are co-contaminants with strong organic chelators, chlorinated solvents, and fuel hydrocarbons. Bioremediation can immobilize the actinides, biodegrade the co-contaminants, or both. Actinides at the IV oxidation state are the least soluble, and microorganisms accelerate precipitation by altering the actinide's oxidation state or its speciation. We describe how microorganisms directly oxidize or reduce actinides and how microbiological reactions that biodegrade strong organic chelators, alter the pH, and consume or produce precipitating anions strongly affect actinide speciation and, therefore, mobility. We explain why inhibition caused by chemical or radiolytic toxicities uniquely affects microbial reactions. Due to the complex interactions of the microbiological and chemical phenomena, mathematical modeling is an essential tool for research on and application of bioremediation involving co-contamination with actinides. We describe the development of mathematical models that link microbiological and geochemical reactions. Throughout, we identify the key research needs

  10. The Use of Molybdenum-Based Ceramic-Metal (CerMet) Fuel for the Actinide Management in LWRs

    The technical and economic aspects of the use of molybdenum depleted in the isotope 95Mo (DepMo) for the transmutation of actinides in a light water reactor are discussed. DepMo has a low neutron absorption cross section and good physical and chemical properties. Therefore, DepMo is expected to be a good inert matrix in ceramic-metal fuel. The costs of the use of DepMo have been assessed, and it was concluded that these costs can be justified for the transmutation of the actinides neptunium, americium, and plutonium

  11. Preparation of actinide targets by electrodeposition

    Trautmann, N.; Folger, H.

    1989-10-01

    Actinide targets with varying thicknesses on different substrates have been prepared by electrodeposition either from aqueous solutions or from solutions of their nitrates in isopropyl alcohol. With these techniques the actinides can be deposited almost quantitatively on various backing materials within 15 to 30 min. Targets of thorium, uranium, neptunium, plutonium, americium, curium and californium with areal densities from almost carrier-free up to 1.4 mg/cm 2 on thin beryllium, carbon, titanium, tantalum and platinum foils have been prepared. In most cases, prior to the deposition, the actinides had to be purified chemically and for some of them, due to the limited amount of material available, recycling procedures were required. Applications of actinide targets in heavy-ion reactions are briefly discussed.

  12. Actinide research to solve some practical problems

    The following topics are discussed: generation of plutonium inventories by nuclear power plants; resettlement of the Marshallese Islanders into an actinide contaminated environment; high radiation background areas of the world; and radiation hazards to uranium miners

  13. Overview of actinide chemistry in the WIPP

    Borkowski, Marian [Los Alamos National Laboratory; Lucchini, Jean - Francois [Los Alamos National Laboratory; Richmann, Michael K [Los Alamos National Laboratory; Reed, Donald T [Los Alamos National Laboratory; Khaing, Hnin [Los Alamos National Laboratory; Swanson, Juliet [Los Alamos National Laboratory

    2009-01-01

    The year 2009 celebrates 10 years of safe operations at the Waste Isolation Pilot Plant (WIPP), the only nuclear waste repository designated to dispose defense-related transuranic (TRU) waste in the United States. Many elements contributed to the success of this one-of-the-kind facility. One of the most important of these is the chemistry of the actinides under WIPP repository conditions. A reliable understanding of the potential release of actinides from the site to the accessible environment is important to the WIPP performance assessment (PA). The environmental chemistry of the major actinides disposed at the WIPP continues to be investigated as part of the ongoing recertification efforts of the WIPP project. This presentation provides an overview of the actinide chemistry for the WIPP repository conditions. The WIPP is a salt-based repository; therefore, the inflow of brine into the repository is minimized, due to the natural tendency of excavated salt to re-seal. Reducing anoxic conditions are expected in WIPP because of microbial activity and metal corrosion processes that consume the oxygen initially present. Should brine be introduced through an intrusion scenario, these same processes will re-establish reducing conditions. In the case of an intrusion scenario involving brine, the solubilization of actinides in brine is considered as a potential source of release to the accessible environment. The following key factors establish the concentrations of dissolved actinides under subsurface conditions: (1) Redox chemistry - The solubility of reduced actinides (III and IV oxidation states) is known to be significantly lower than the oxidized forms (V and/or VI oxidation states). In this context, the reducing conditions in the WIPP and the strong coupling of the chemistry for reduced metals and microbiological processes with actinides are important. (2) Complexation - For the anoxic, reducing and mildly basic brine systems in the WIPP, the most important

  14. PWRs potentialities for minor actinides burning

    In the frame of the SPIN program at CEA, the impacts of the Minor Actinides (MA) incineration in PWRs are analysed. The aim is to reduce the mass and the potential radiotoxicity level. This study is done separately one on the Plutonium recycling. But the plutonium is essential. Thus, the recycling of all Actinide elements is evaluated in a PWR nuclear yard. A sensitivity study is done to evaluate the incineration for each Minor Actinide element. This gives us the most efficient way of incineration for each MA element in a PWR and help us to design a PWR burner. This burner is disposed in a PWR nuclear system in which the Actinides are recycled until equilibrium. (authors). 2 refs

  15. Electronic structure and correlation effects in actinides

    Albers, R.C.

    1998-12-01

    This report consists of the vugraphs given at a conference on electronic structure. Topics discussed are electronic structure, f-bonding, crystal structure, and crystal structure stability of the actinides and how they are inter-related.

  16. Advanced Aqueous Separation Systems for Actinide Partitioning

    Nash, Kenneth L.; Clark, Sue; Meier, G Patrick; Alexandratos, Spiro; Paine, Robert; Hancock, Robert; Ensor, Dale

    2012-03-21

    One of the most challenging aspects of advanced processing of spent nuclear fuel is the need to isolate transuranium elements from fission product lanthanides. This project expanded the scope of earlier investigations of americium (Am) partitioning from the lanthanides with the synthesis of new separations materials and a centralized focus on radiochemical characterization of the separation systems that could be developed based on these new materials. The primary objective of this program was to explore alternative materials for actinide separations and to link the design of new reagents for actinide separations to characterizations based on actinide chemistry. In the predominant trivalent oxidation state, the chemistry of lanthanides overlaps substantially with that of the trivalent actinides and their mutual separation is quite challenging.

  17. BWR Assembly Optimization for Minor Actinide Recycling

    G. Ivan Maldonado; John M. Christenson; J.P. Renier; T.F. Marcille; J. Casal

    2010-03-22

    The Primary objective of the proposed project is to apply and extend the latest advancements in LWR fuel management optimization to the design of advanced boiling water reactor (BWR) fuel assemblies specifically for the recycling of minor actinides (MAs).

  18. Analysis of the minority actinides transmutation in a sodium fast reactor with uniform load pattern by the MCNPX-CINDER code; Analisis de la transmutacion de actinidos en un reactor rapido de sodio con modelo de carga homogeneo mediante el codigo MCNPX-CINDER

    Ochoa Valero, R.; Garcia-Herranz, N.; Aragones, J. M.

    2010-07-01

    The aim of this study is to evaluate the minority actinides transmutation in sodium fast reactors (SFR) assuming a uniform load pattern. It is determined the isotopic evolution of the actinides along burn, and the evolution of the reactivity and the reactivity coefficients. For that, it is used the MCNPX neutron transport code coupled with the inventory code CINDER90.

  19. Utilization of Carbon Isotope Discrimination and Ash Content to Select Wheat for Tolerance to Water Limitation in the Peninsular Zone of India

    Relationships between grain yield, ash content (ma) and carbon isotope discrimination (CID, Δ13C or Δ) were studied in 30 wheat genotypes (14 durum and 16 aestivum) during 2003-2004, and 20 durum genotypes during two successive seasons (2004-2005 and 2005-2006) under three water regimes, i.e., residual soil moisture stress (RSMS), post-anthesis water stress (PAWS) and well watered (WW) conditions. Correlations between grain yield, ash content and Δ depended greatly on the environmental conditions and the drought scenario. Grain yield, biomass, Δ and ma decreased significantly with the reduction in water availability. Yield was significantly and positively correlated with ΔLa and ΔGm for each water regime only in 2005-2006, but the relationships were significant under WW across seasons. Strong negative correlations were observed between yield and maGm for each water regime only in 2004-2005, but the relationships were significant across seasons under WW conditions. Several significant and negative correlations were observed between yield and canopy temperature depression, but the relationships were significant only under PAWS across seasons. Results obtained during 2004-2005 and 2005-2006 show that Δ and maGm could consistently predict yield only under WW conditions. ΔGm and ΔLa were consistently and significantly correlated with maLa only under RSMS. In RIL population studies a major QTL was detected on chromosome 4B, responsible for around 15% of the variation in Δ. Major QTLs for canopy temperature depression (CTD) were identified on chromosomes 2A and 6A, and major QTLs for ash content were detected on chromosomes 5A and 6A, under PAWS and full irrigation, respectively. Near Infra-red transmittance (NIT) was used to speed up the determination of grain ash content. The overall range for wheat samples analyzed by the reference and NIT methods were 1.2 - 2.3 % and 1.22 - 1.99% (dry weight basis), respectively. The slope of the regression was 1.000 with an

  20. Chemistry of tetravalent actinides phosphates. The thorium phosphate-diphosphate as immobilisation matrix of actinides; Chimie des phosphates d'actinides tetravalents. Le phosphate-diphosphate de thorium en tant que matrice d'imobilisation des actinides

    Dacheux, N

    2002-07-01

    The author presents in this document its scientific works from 1992 to 2001, in order to obtain the enabling to manage scientific and chemical researches at the university Paris Sud Orsay. The first part gives an abstract of the thesis on the characterizations, lixiviation and synthesis of uranium and thorium based phosphate matrix in the framework of the search for a ceramic material usable in the radioactive waste storage. The second part presents briefly the researches realized at the CEA, devoted to a reliable, independent and accurate measure of some isotopes activity. The last part presents the abstracts of researches activities from 1996 to 2001 on the tetravalent actinides phosphates chemistry, the sintering of PDT and solid solutions of PDTU and the kinetic and thermodynamical studies of the PDT dissolution. Many references and some publication in full text are provided. (A.L.B.)

  1. Lanthanides and actinides in ionic liquids

    Binnemans, Koen

    2007-01-01

    This lecture gives an overview of the research possibilities offered by combining f-elements (lanthanides and actinides) with ionic liquids [1] Many ionic liquids are solvents with weakly coordinating anions. Solvation of lanthanide and actinide ions in these solvents is different from what is observed in conventional organic solvents and water. The poorly solvating behavior can also lead to the formation of coordination compounds with low coordination numbers. The solvation of f-elements can...

  2. New molecules to separate actinides: the picolinamides

    The reprocessing of spent fuel is made with the Purex process, funded on liquid-liquid extraction of uranium nitrates(VI) and plutonium nitrates(IV) by the BTP (tributyl phosphate). To improve this proceeding, we look for extractants which allow, beyond U and Pu extractions, these of actinides (II) and allow separation of the whole actinides from the fission products, which have an important fraction of lanthanides. A new family seems to give good results: the picolinamides

  3. Superconductivity in rare earth and actinide compounds

    Rare earth and actinide compounds and the extraordinary superconducting and magnetic phenomena they exhibit are surveyed. The rare earth and actinide compounds described belong to three classes of novel superconducting materials: high temperature, high field superconductors (intermetallics and layered cuprates); superconductors containing localized magnetic moments; heavy fermion superconductors. Recent experiments on the resistive upper critical field of high Tc cuprate superconductors and the peak effect in the critical current density of the f-electron superconductor CeRu2 are discussed. (orig.)

  4. Lattice effects in the light actinides

    The light actinides show a variety of lattice effects that do not normally appear in other regions of the periodic table. The article will cover the crystal structures of the light actinides, their atomic volumes, their thermal expansion behavior, and their elastic behavior as reflected in recent thermal vibration measurements made by neutron diffraction. A discussion of the melting points will be given in terms of the thermal vibration measurements. Pressure effects will be only briefly indicated

  5. Actinide solubility in deep groundwaters - estimates for upper limits based on chemical equilibrium calculations

    A chemical equilibrium model is used to estimate maximum upper concentration limits for some actinides (Th, U, Np, Pu, Am) in groundwaters. Eh/pH diagrams for solubility isopleths, dominant dissolved species and limiting solids are constructed for fixed parameter sets including temperature, thermodynamic database, ionic strength and total concentrations of most important inorganic ligands (carbonate, fluoride, phosphate, sulphate, chloride). In order to assess conservative conditions, a reference water is defined with high ligand content and ionic strength, but without competing cations. In addition, actinide oxides and hydroxides are the only solid phases considered. Recommendations for 'safe' upper actinide solubility limits for deep groundwaters are derived from such diagrams, based on the predicted Eh/pH domain. The model results are validated as far as the scarce experimental data permit. (Auth.)

  6. A 15 000-year record of climate change in northern New Mexico, USA, inferred from isotopic and elemental contents of bog sediments

    Cisneros-Dozal, L. M.; Heikoop, J.M.; Fessenden, J.; Anderson, R. Scott; Meyers, P.A.; Allen, C.D.; Hess, M.; Larson, T.; Perkins, G.; Rearick, M.

    2010-01-01

    Elemental (C, N, Pb) and isotopic (??13C, ??15N) measurements of cored sediment from a small bog in northern New Mexico reveal changes in climate during the Late Pleistocene and Holocene. Abrupt increases in Pb concentration and ??13C values ca. 14 420 cal. YBP indicate significant runoff to the shallow lake that existed at that time. Weathering and transport of local volcanic rocks resulted in the delivery of Pb-bearing minerals to the basin, while a 13C-enriched terrestrial vegetation source increased the ??13C values of the sedimentary material. Wet conditions developed over a 300 a period and lasted for a few hundred years. The Younger Dryas period (ca. 12 700-11 500 cal. YBP) caused a reduction in terrestrial productivity reflected in decreasing C/N values, ??15N values consistently greater than 0??? and low organic content. By contrast, aquatic productivity increased during the second half of this period, evidenced by increasing ??13C values at the time of highest abundance of algae. Dry conditions ca. 8 000-6 000 cal. YBP were characterised by low organic carbon content and high Pb concentrations, the latter suggesting enhanced erosion and aeolian transport of volcanic rock. The range in ??13C, ??15N and C/N values in the sedimentary record fall within the range of modern plants, except during the periods of runoff and drought. The sedimentary record provides evidence of natural climate variability in northern New Mexico, including short- (multi-centennial) and long-(millennial) term episodes during the Late Pleistocene and Holocene. Copyright ?? 2010 John Wiley & Sons, Ltd.

  7. Gastrointestinal absorption of actinides: a review with special reference to primate data

    Large scale geological burial of transuranic wastes from fission power production may expose segments of future generations to trace amounts of actinides in water and food, which, via gastrointestinal absorption, could result in internal doses of alpha radiation. Gastrointestinal absorption of actinide elements is a poorly understood process. Experimental studies, primarily using rodents, often produce ambiguous results with order of magnitude fluctuations in estimates of GI absorption. Since experimental conditions like the chemical form of the fed actinides or reducing and complexing capacity of the stomach content, influence the GI transfer factor in seemingly unpredictable ways, only a better understanding of events at the molecular level will enable more reliable predictions to be made of the organ burdens resulting from actinides passing through the digestive tract. From a review of the existing literature it is apparent that in vitro research data in the area of GI uptake mechanisms (i.e. transport mediated by ion carriers in body fluids and across cell membranes) are virtually non-existant. In view of the uncertainties linked to in vivo uptake experiment, models which approximate man, i.e. derived from non-human primate studies, should be the best choice of experimental systems in which to determine reliable estimates for gastrointestinal transfer factors of actinide elements. (Auth.)

  8. Measurements of minor actinides cross sections for transmutation

    The existing reactors produce two kinds of nuclear waste: the fission products and heavy nuclei beyond uranium called minor actinides (Americium and Curium isotopes). Two options are considered: storage in deep geological site and/or transmutation by fast neutron induced fission. These studies involve many neutron data. Unfortunately, these data bases have still many shortcomings to achieve reliable results. The aim of these measurements is to update nuclear data and complement them. We have measured the fission cross section of 243Am (7370 y) in reference to the (n,p) elastic scattering to provide new data in a range of fast neutrons (1-8 MeV). A statistical model has been developed to describe the reaction 243Am (n,f). Moreover, the cross sections from the following reactions have been be extracted from these calculations: inelastic scattering 243Am (n,n') and radiative capture 243Am (n,γ) cross sections. The direct measurements of neutron cross sections are often a challenge considering the short half-lives of minor actinides. To overcome this problem, a surrogate method using transfer reactions has been used to study few isotopes of curium. The reactions 243Am (3He, d)244Cm, 243Am (3He, t)243Cm and 243Am (3He, α)242Am allowed to measure the fission probabilities of 243,244Cm and 242Am. The fission cross sections of 242,243Cm (162,9 d, 28,5 y) and 241Am (431 y) have been obtained by multiplying these fission probabilities by the calculated compound nuclear neutron cross section relative to each channel. For each measurement, an accurate assessment of the errors was realized through variance-covariance studies. For measurements of the reaction 243Am(n,f), the analysis of error correlations allowed to interpret the scope of these measures within the existing measurements. (author)

  9. Evaluation of actinide partitioning and transmutation

    After a few centuries of radioactive decay the long-lived actinides, the elements of atomic numbers 89-103, may constitute the main potential radiological health hazard in nuclear wastes. This is because all but a very few fission products (principally technetium-99 and iodine-129) have by then undergone radioactive decay to insignificant levels, leaving the actinides as the principal radionuclides remaining. It was therefore at first sight an attractive concept to recycle the actinides to nuclear reactors, so as to eliminate them by nuclear fission. Thus, investigations of the feasibility and potential benefits and hazards of the concept of 'actinide partitioning and transmutation' were started in numerous countries in the mid-1970s. This final report summarizes the results and conclusions of technical studies performed in connection with a four-year IAEA Co-ordinated Research Programme, started in 1976, on the ''Environmental Evaluation and Hazard Assessment of the Separation of Actinides from Nuclear Wastes followed by either Transmutation or Separate Disposal''. Although many related studies are still continuing, e.g. on waste disposal, long-term safety assessments, and waste actinide management (particularly for low and intermediate-level wastes), some firm conclusions on the overall concept were drawn by the programme participants, which are reflected in this report

  10. Recent progress in actinide borate chemistry.

    Wang, Shuao; Alekseev, Evgeny V; Depmeier, Wulf; Albrecht-Schmitt, Thomas E

    2011-10-21

    The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB(5)O(6)(OH)(6)][BO(OH)(2)]·2.5H(2)O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO(4)(-). Uranyl borates form noncentrosymmetric structures with extraordinarily rich topological relationships. Neptunium borates are often mixed-valent and yield rare examples of compounds with one metal in three different oxidation states. Plutonium borates display new coordination chemistry for trivalent actinides. Finally, americium borates show a dramatic departure from plutonium borates, and there are scant examples of families of actinides compounds that extend past plutonium to examine the bonding of later actinides. There are several grand challenges that this work addresses. The foremost of these challenges is the development of structure-property relationships in transuranium materials. A deep understanding of the materials chemistry of actinides will likely lead to the development of advanced waste forms for radionuclides present in nuclear waste that prevent their transport in the environment. This work may have also uncovered the solubility-limiting phases of actinides in some repositories, and allows for measurements on the stability of these materials. PMID:21915396

  11. Fast neutron capture in actinide isotopes: recent results from Karlsruhe

    Capture gamma-ray spectra of 241Am, 240Pu, 242Pu 238U and 197Au were calculated in the framework of the spherical optical model and the statistical model. These spectra were used to correct experimental data for the capture cross sections of 240242Pu and 241Am from relative measurements using a Moxon Rae-detector with graphite converter and 197Au as well as 238U as standards. This correction is required to take into account that the detector efficiency is not exactly proportional to gamma-ray energy. The resulting correction factors proved to be negligible for measurements relative to 238U, whereas they are approx. 3% if gold is used as a standard. The capture cross section of 243Am has been measured in the energy range 10 to 250 keV using kinematically collimated neutrons from the 7Li(p,n) and T(p,n) reaction. The samples are positioned at flight paths of 5 to 7 cm and gold was used as a standard. Capture events were detected by two Moxon-Rae detectors with graphite and bismuth-graphite converters shielded by 0.5 to 2 cm of lead. Fission events were detected by a NE213 liquid scintillator. The present status of the experiment and some preliminary results will be presented

  12. Georgia Institute of Technology research on the Gas Core Actinide Transmutation Reactor (GCATR)

    Clement, J. D.; Rust, J. H.; Schneider, A.; Hohl, F.

    1976-01-01

    The program reviewed is a study of the feasibility, design, and optimization of the GCATR. The program is designed to take advantage of initial results and to continue work carried out on the Gas Core Breeder Reactor. The program complements NASA's program of developing UF6 fueled cavity reactors for power, nuclear pumped lasers, and other advanced technology applications. The program comprises: (1) General Studies--Parametric survey calculations performed to examine the effects of reactor spectrum and flux level on the actinide transmutation for GCATR conditions. The sensitivity of the results to neutron cross sections are to be assessed. Specifically, the parametric calculations of the actinide transmutation are to include the mass, isotope composition, fission and capture rates, reactivity effects, and neutron activity of recycled actinides. (2) GCATR Design Studies--This task is a major thrust of the proposed research program. Several subtasks are considered: optimization criteria studies of the blanket and fuel reprocessing, the actinide insertion and recirculation system, and the system integration. A brief review of the background of the GCATR and ongoing research is presented.

  13. Study of crystalline actinide waste forms produced by self-propagating high-temperature synthesis

    Prospective matrices for a safe immobilisation of long-lived actinide-bearing wastes were produced by self-propagating high-temperature synthesis. The samples were examined using XRD, SEM/EDS, and TEM. The data show that the ceramics consist of oxide phases with a fluorite- or pyrochlore-type structure and also metallic Mo. The structural properties of the target actinide-loaded host phase depend primarily on the composition of the immobilised waste. It is suggested that for streams enriched with tetravalent actinides having relatively small dimension of the cations: U4+ (0.10 nm), Np4+ (0.098 nm), and Pu4+ (0.096 nm), a cubic fluorite-structured ZrO2-based solid solution can be used to fix the waste, whereas titanates or zirconates with a pyrochlore-type lattice are well suited for wastes containing large amounts of the bulkier ions of trivalent actinides (Pu3+, Am3+) and lanthanides (Nd, Ce, La, Pr). Among other elements which can be located into the octahedral sites of the pyrochlore lattice, Tc4+ with a radius of 0.065 nm is worth mentioning. Long-lived 99Tc is produced during 235U fission events. Due to a high hazard associated with this isotope, it should also be fixed in highly durable matrices such as pyrochlore

  14. FY2011 Annual Report for the Actinide Isomer Detection Project

    Warren, Glen A.; Francy, Christopher J.; Ressler, Jennifer J.; Erikson, Luke E.; Tatishvili, Gocha; Hatarik, R.

    2011-10-01

    This project seeks to identify a new signature for actinide element detection in active interrogation. This technique works by exciting and identifying long-lived nuclear excited states (isomers) in the actinide isotopes and/or primary fission products. Observation of isomers in the fission products will provide a signature for fissile material. For the actinide isomers, the decay time and energy of the isomeric state is unique to a particular isotope, providing an unambiguous signature for SNM. This project entails isomer identification and characterization and neutron population studies. This document summarizes activities from its third year - completion of the isomer identification characterization experiments and initialization of the neutron population experiments. The population and decay of the isomeric state in 235U remain elusive, although a number of candidate gamma rays have been identified. In the course of the experiments, a number of fission fragment isomers were populated and measured [Ressler 2010]. The decays from these isomers may also provide a suitable signature for the presence of fissile material. Several measurements were conducted throughout this project. This report focuses on the results of an experiment conducted collaboratively by PNNL, LLNL and LBNL in December 2010 at LBNL. The measurement involved measuring the gamma-rays emitted from an HEU target when bombarded with 11 MeV neutrons. This report discussed the analysis and resulting conclusions from those measurements. There was one strong candidate, at 1204 keV, of an isomeric signature of 235U. The half-life of the state is estimated to be 9.3 {mu}s. The measured time dependence fits the decay time structure very well. Other possible explanations for the 1204-keV state were investigated, but they could not explain the gamma ray. Unfortunately, the relatively limited statistics of the measurement limit, and the lack of understanding of some of the systematic of the experiment, limit

  15. Oak Ridge National Laboratory's isotope enrichment program

    The Isotope Enrichment Program (IEP) at Oak Ridge National Laboratory (ORNL) is responsible for the production and distribution of ∼225 enriched stable isotopes from 50 multi-isotopic elements. In addition, ORNL distributes enriched actinide isotopes and provides extensive physical- and chemical-form processing of enriched isotopes to meet customer requirements. For more than 50 yr, ORNL has been a major provider of enriched isotopes and isotope-related services to research, medical, and industrial institutions throughout the world. Consolidation of the Isotope Distribution Office (IDO), the Isotope Research Materials Laboratory (IRML), and the stable isotope inventories in the Isotope Enrichment Facility (IEF) have improved operational efficiencies and customer services. Recent changes in the IEP have included adopting policies for long-term contracts, which offer program stability and pricing advantages for the customer, and prorated service charges, which greatly improve pricing to the small research users. The former U.S. Department of Energy (DOE) Loan Program has been converted to a lease program, which makes large-quantity or very expensive isotopes available for nondestructive research at a nominal cost. Current efforts are being pursued to improve and expand the isotope separation capabilities as well as the extensive chemical- and physical-form processing that now exists. The IEF's quality management system is ISO 9002 registered and accredited in the United States, Canada, and Europe

  16. Actinide transmutation in nuclear reactors

    An optimization method is developed to maximize the burning capability of the ALMR while complying with all constraints imposed on the design for reliability and safety. This method leads to a maximal transuranics enrichment, which is being limited by constraints on reactivity. The enrichment can be raised by using the neutrons less efficiently by increasing leakage from the fuel. With the developed optimization method, a metallic and an oxide fueled ALMR were optimized. Both reactors perform equally well considering the burning of transuranics. However, metallic fuel has a much higher heat conductivity coefficient, which in general leads to better safety characteristics. In search of a more effective waste transmuter, a modified Molten Salt Reactor was designed. A MSR operates on a liquid fuel salt which makes continuous refueling possible, eliminating the issue of the burnup reactivity loss. Also, a prompt negative reactivity feedback is possible for an overmoderated reactor design, even when the Doppler coefficient is positive, due to the fuel expansion with fuel temperature increase. Furthermore, the molten salt fuel can be reprocessed based on a reduction process which is not sensitive to the short-lived spontaneously fissioning actinides. (orig./HP)

  17. Measurement of electro-sprayed 238 and 239+240 plutonium isotopes using 4{pi}-alpha spectrometry. Application to environmental samples; Spectrometrie alpha 4{pi} de sources d'actinides realisees par electronebulisation. Developpement et optimisation d'un protocole applique au mesurage des isotopes 238 et 239+240 du plutonium dans l'environnement

    Charmoille-Roblot, M. [CEA/Fontenay-aux-Roses, Dept. de Protection de l' Environnement (DPRE), 92 (France)]|[Paris-11 Univ., 91 - Orsay (France)

    1999-07-01

    A new protocol for plutonium deposition using the electro-spray technique coupled with 4{pi}-{alpha} spectrometry is proposed to improve the detection limit, shorten the counting time. In order to increase the detection efficiency, it was proposed to measure 238 and 239+240 plutonium isotopes electro-sprayed deposit simultaneously on both sides of the source support, that must be as transparent as possible to alpha-emissions, in a two-alpha detectors chamber. A radiochemical protocol was adapted to electro-spray constraints and a very thin carbon foil was selected for 4{pi} -alpha spectrometry. The method was applied to a batch of sediment samples and gave the same results as an electrodeposited source measured using conventional alpha spectrometry with a 25 % gain on counting time and 10 % on plutonium 238 detection limit. Validation and application of the technique have been made on reference samples. (author)

  18. Lipid biomarkers for anaerobic oxidation of methane and sulphate reduction in cold seep sediments of Nyegga pockmarks (Norwegian margin): discrepancies in contents and carbon isotope signatures

    Chevalier, Nicolas; Bouloubassi, Ioanna; Stadnitskaia, Alina; Taphanel, Marie-Hélène; Sinninghe Damsté, Jaap S.

    2014-06-01

    Distributions and carbon isotopic compositions of microbial lipid biomarkers were investigated in sediment cores from the G11 and G12 pockmarks in the Nyegga sector of the Storegga Slide on the mid-Norwegian margin to explore differences in depth zonation, type and carbon assimilation mode of anaerobic methane-oxidizing archaea (ANMEs) and associated sulphate-reducing bacteria responsible for anaerobic oxidation of methane (AOM) in these cold seep environments. While the G11 site is characterised by black reduced sediments colonized by gastropods and Siboglinidae tubeworms, the G12 site has black reduced sediments devoid of fauna but surrounded by a peripheral occurrence of gastropods and white filamentous microbial mats. At both sites, bulk sediments contained abundant archaeal and bacterial lipid biomarkers substantially depleted in 13C, consisting mainly of isoprenoidal hydrocarbons and dialkyl glycerol diethers, fatty acids and non-isoprenoidal monoalkylglycerol ethers. At the G11 site, down-core profiles revealed that lipid biomarkers were in maximum abundance from 10 cm depth to the core bottom at 16 cm depth, associated with δ13C values of -57 to -136‰. At the G12 site, by contrast, lipid biomarkers were in high abundance in the upper 5 cm sediment layer, associated with δ13C values of -43 to -133‰. This suggests that, as expected from the benthic fauna characteristics of the sites, AOM takes place mainly at depth in the G11 pockmark but just below the seafloor in the G12 pockmark. These patterns can be explained largely by variable fluid flow rates. Furthermore, at both sites, a dominance of ANME-2 archaea accompanied by their bacterial partners is inferred based on lipid biomarker distributions and carbon isotope signatures, which is in agreement with recently published DNA analyses for the G11 pockmark. However, the present data reveal high discrepancies in the contents and δ13C values for both archaeal and bacterial lipid profiles, implying the

  19. Fabrication and Pre-irradiation Characterization of a Minor Actinide and Rare Earth Containing Fast Reactor Fuel Experiment for Irradiation in the Advanced Test Reactor

    Timothy A. Hyde

    2012-06-01

    The United States Department of Energy, seeks to develop and demonstrate the technologies needed to transmute the long-lived transuranic actinide isotopes contained in spent nuclear fuel into shorter lived fission products, thereby decreasing the volume of material requiring disposal and reducing the long-term radiotoxicity and heat load of high-level waste sent to a geologic repository. This transmutation of the long lived actinides plutonium, neptunium, americium and curium can be accomplished by first separating them from spent Light Water Reactor fuel using a pyro-metalurgical process, then reprocessing them into new fuel with fresh uranium additions, and then transmuted to short lived nuclides in a liquid metal cooled fast reactor. An important component of the technology is developing actinide-bearing fuel forms containing plutonium, neptunium, americium and curium isotopes that meet the stringent requirements of reactor fuels and materials.

  20. Solubility of actinide surrogates in nuclear glasses

    This paper discusses the results of a study of actinide surrogates in a nuclear borosilicate glass to understand the effect of processing conditions (temperature and oxidizing versus reducing conditions) on the solubility limits of these elements. The incorporation of cerium oxide, hafnium oxide, and neodymium oxide in this borosilicate glass was investigated. Cerium is a possible surrogate for tetravalent and trivalent actinides, hafnium for tetravalent actinides, and neodymium for trivalent actinides. The material homogeneity was studied by optical, scanning electron microscopy. Cerium LIII XANES spectroscopy showed that the Ce3+/Cetotal ratio increased from about 0.5 to 0.9 as the processing temperature increased from 1100 to 1400 deg. C. Cerium LIII XANES spectroscopy also confirmed that the increased Ce solubility in glasses melted under reducing conditions was due to complete reduction of all the cerium in the glass. The most significant results pointed out in the current study are that the solubility limits of the actinide surrogates increases with the processing temperature and that Ce3+ is shown to be more soluble than Ce4+ in this borosilicate glass

  1. Waste disposal aspects of actinide separation

    Two recent NRPB reports are summarized (Camplin, W.C., Grimwood, P.D. and White, I.F., The effects of actinide separation on the radiological consequences of disposal of high-level radioactive waste on the ocean bed, Harwell, National Radiological Protection Board, NRPB-R94 (1980), London, HMSO; Hill, M.D., White, I.F. and Fleishman, A.B., The effects of actinide separation on the radiological consequences of geologic disposal of high-level waste. Harwell, National Radiological Protection Board, NRPB-R95 (1980), London, HMSO). They describe preliminary environmental assessments relevant to waste arising from the reprocessing of PWR fuel. Details are given of the modelling of transport of radionuclides to man, and of the methodology for calculating effective dose equivalents in man. Emphasis has been placed on the interaction between actinide separation and the disposal options rather than comparison of disposal options. The reports show that the effects of actinide separation do depend on the disposal method. Conditions are outlined where the required substantial further research and development work on actinide separation and recycle would be justified. Toxicity indices or 'toxic potentials' can be misleading and should not be used to guide research and development. (U.K.)

  2. TUCS/phosphate mineralization of actinides

    Nash, K.L. [Argonne National Lab., IL (United States)

    1997-10-01

    This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

  3. Build-Up Of Actinides In Irradiated Fuel Rods Of The ETRR-1 Reactor

    The content concentrations of actinides are calculated as a function of operating reactor regime and cooling time at different percentage of fuel burn-up. The build-up transmutation equations of actinides content in an irradiated fuel are solved numerically .A computer code BAC was written to operate on PC computer to provide the required calculations. The fuel element of 10% 235U enrichment of ETRR-1 reactor was taken as an example for calculations using BAC code. The results are compared with other calculations for the ETRR-1 fuel rod. An estimation of fissile build-up content of a proposed new fuel of 20% '235U enrichment for ETRR-1 reactor is given. The sensitivity coefficients of build-up plutonium concentrations as a function of cross-section data uncertainties are also calculated

  4. Build up of actinides in burnt fuel rods of the ET-RR-1 reactor

    The content concentrations of actinides are calculated as a function of operating reactor regime and cooling time at different percentage of fuel burn-up. The build-up transmutation equations of actinides content in an irradiated fuel are solved numerically .A computer code BAC was written to operate on a PC computer to provide the required calculations. The fuel element of 10% 235U enrichment of ET-RR-1 reactor was taken as an example for calculations using the BAC code. The results are compared with other calculations for the ET-RR-1 fuel rod. An estimation of fissile build-up content of a proposed new fuel of 20% 235U enrichment for ET-RR-1 reactor is given. The sensitivity coefficients of build-up plutonium concentrations as a function of cross-section data uncertainties are also calculated. (author)

  5. New reagents for actinide-lanthanide group separations

    Organic extractants which possess nitrogen or sulfur donor atoms preferentially complex the trivalent actinide. They are potential reagents for actinide lanthanide group separations, which can be performed at low pH without the addition of inorganic salts

  6. Radio-ecological researches in the Sea of Japan and northwestern part of the Pacific Ocean after accident on the Japanese nuclear power plant 'Fukushima-1': the content of plutonium isotopes and strontium-90 in sea water

    Fedorova, A. [Research and Production Association - RPA Typhoon (Russian Federation)

    2014-07-01

    In April-May 2011 and in August-September 2012 'Roshydromet' has conducted radio ecological researches in the Sea of Japan and on the water area of northwestern part of the Pacific Ocean (Kuril-Kamchatka area and the area of the Kuroshio current), which had purpose to make assessment of contamination hazard that can be caused to the coast of Russian Far East because of emergency releases of radioactive materials on the nuclear power plant 'Fukushima-1'. During the research works was done the sampling and processing of sea water samples not only for detection of Cs{sup 134}, Cs{sup 137}, but also for such radio-ecological significant long-living radionuclides, as {sup 90}Sr, plutonium isotopes ({sup 239,240}Pu) and tritium. Information about radionuclides was required for correct assessment of nuclear power plant 'Fukushima-1' aftermath on the Far Eastern sea water areas, but was not available in the beginning of research. In the present report the radiochemical measuring results on content of plutonium isotopes and {sup 90}Sr in the sea water from researched areas are presented. Sampling was done from the various horizons. Surface and deep water samples were filtered via the compound filter which made it possible to filter particles bigger than 1 micron. Radiochemical testing of the {sup 90}Sr and plutonium isotopes content was done separately on a suspension and in a filtrate of sea water samples. The content of {sup 90}Sr in the filtrate of the sea water that had been selected in 2011, ranges 0,7-2,4 Bq/m{sup 3}, in suspensions the interval makes 0,0013-0,021 Bq/m3. The results received in researches in 2012 are in range of 0,5-2,6 Bq/m{sup 3} of the sea water filtrate. According to results of IAEA in 2000, the average content of {sup 90}Sr in surface water of the Sea of Japan made 1,6 Bq/m{sup 3}. Hereby, the data obtained in researches in 2011-2012 agrees with results which had been presented by IAEA before the accident. The

  7. Dounreay PFR irradiation history for the joint US/UK actinide sample exposures

    The operating history of the Dounreay Prototype Fast Reactor is presented to the extent that it is relevant to the irradiation of actinide specimens that were subsequently analyzed at Oak Ridge National Laboratory (ORNL). Three fuel pins with actinide samples were irradiated from July 1982 to July 1988 and returned to ORNL for analysis. They contained isotopes of elements from thorium to curium. The times when each of these fuel pins were in the reactor core are described as are the operating power levels and neutron spectra. The appendices give daily power levels of the reactor as well as six-group neutron energy spectra for various times and axial positions in the core

  8. STRONTIUM AND ACTINIDE SEPARATIONS FROM HIGH LEVEL NUCLEAR WASTE SOLUTIONS USING MONOSODIUM TITANATE 1. SIMULANT TESTING

    HOBBS, D. T.; BARNES, M. J.; PULMANO, R. L.; MARSHALL, K. M.; EDWARDS, T. B.; BRONIKOWSKI, M. G.; FINK, S. D.

    2005-04-14

    High-level nuclear waste produced from fuel reprocessing operations at the Savannah River Site (SRS) requires pretreatment to remove {sup 137}Cs, {sup 90}Sr and alpha-emitting radionuclides (i.e., actinides) prior to disposal. Separation processes planned at SRS include caustic side solvent extraction, for {sup 137}Cs removal, and ion exchange/sorption of {sup 90}Sr and alpha-emitting radionuclides with an inorganic material, monosodium titanate (MST). The predominant alpha-emitting radionuclides in the highly alkaline waste solutions include plutonium isotopes {sup 238}Pu, {sup 239}Pu and {sup 240}Pu. This paper provides a summary of data acquired to measure the performance of MST to remove strontium and actinides from simulated waste solutions. These tests evaluated the influence of ionic strength, temperature, solution composition and the oxidation state of plutonium.

  9. Strontium and Actinides Removal from Savannah River Site Actual Waste Samples by Freshly Precipitated Manganese Oxide

    The authors investigated the performance of freshly precipitated manganese oxide and monosodium titanate (MST) for the removal of strontium (Sr) and actinides from actual high-level waste. Manganese oxide precipitation occurs upon addition of a reductant such as formate (HCO2-) or peroxide (H2O2) to a waste solution containing permanganate (MnO4-). An addition of non-radioactive strontium typically precedes the MnO4- and reductant addition, which serves primarily to isotopically dilute the strontium-90 (90Sr) present in the waste. Tests utilized a Tank 37H/44F composite waste solution. Personnel significantly increased the concentration of actinides in the waste by the addition of acidic americium/curium solution (F-Canyon Tank 17.1 solution), which contained a significant quantity of plutonium (Pu), and neptunium-237 (237Np) stock solution. Initial tests examined three manganese oxide treatment options

  10. Neutronics design of transmutation of minor actinides in a fusion reactor

    A concept of transmutation of Minor Actinide (MA) nuclear waste based on the spherical torus (ST) tokamak reactor, FDTR, is put forward. A set of plasma parameter was decided suitable for the ST transmuting nuclear waste blanket. The 2-D neutron transport code TWODANT, 3-D Monte Carlo code MCNP-4B and 1-D burn-up calculation code BISON3.0 and their associated data libraries are used to calculate the transmutation rate, the energy multiplication factor and the tritium breeding rate of the transmutation blanket. The calculation results of the system parameters and the actinide series isotopes for different operation times are also given. The engineering feasibility of the center-post of FDTR is investigated. Relevant results are also given. A preliminary neutronics calculation based on ST transmutation blanket shows that proposed system has high transmuting ability for MA wastes

  11. Denaturing of plutonium by transmutation of minor-actinides for enhancement of proliferation resistance

    Feasibility study for the plutonium denaturing by utilizing minor-actinide transmutation in light water reactors has been performed. And the intrinsic feature of proliferation resistance of plutonium has been discussed based on IAEA's publication and Kessler's proposal. The analytical results show that not only 238Pu but also other plutonium isotopes with even-mass-number have very important role for denaturing of plutonium due to their relatively large critical mass and noticeably high spontaneous fission neutron generation. With the change of the minor-actinide doping ratio in U-Pu mix oxide fuel and moderator to fuel ratio, it is found that the reactor-grade plutonium from conventional light water reactors can be denatured to satisfy the proliferation resistance criterion based on the Kessler's proposal but not to be sufficient for the criterion based on IAEA's publication. It has been also confirmed that all the safety coefficients take negative value throughout the irradiation. (author)

  12. Isotopes in hydrogeology

    Questions of the application of radioactive isotopes in hydrogeology and seismology are considered, as well as their physico-chemical and geochemical properties and the regularities of their occurrence and migration in natural waters. The possibility of application of these isotopes in calculating the age of waters and in solving paleohydrogeological problems is studied. Elucidated are questions of utilization of helium and uranium isotope content in determining the effect of faults on the hydrogeological conditions of regions and in selecting burial sites for industrial wastes. Utilization of changes in the isotopic and gas composition of underground waters during the activization of tectonic movements for earthquake forecasts is considered

  13. Separation of actinides with alkylpyridinium salts

    Various f-elements are separated as anionic complexes from both acidic and alkaline solutions by precipitation with alkylpyridinium salts. The precipitates are also cationic surfactants where the simple counter-ion (e.g. nitrate or chloride) is replaced by the negatively charged complex anion of an actinide or lanthanide. The low solubility of these precipitates is explained by a strong affinity of divalent complex counter-ions of f-elements to the quaternary nitrogen. Precipitations in solutions of nitric acid allow to separate tetravalent f-elements from other metals, in alkaline carbonate solutions tetravalent and hexavalent actinides are precipitated simultaneously. The last procedure yields precipitates, which are very intimate mixtures of hexavalent and tetravalent actinides. This allows to prepare mixed oxides in a simple way. (author) 6 refs.; 3 figs.; 3 tabs

  14. Neutron scattering studies of the actinides

    The electronic structure of actinide materials presents a unique example of the interplay between localized and band electrons. Together with a variety of other techniques, especially magnetization and the Mossbauer effect, neutron studies have helped us to understand the systematics of many actinide compounds that order magnetically. A direct consequence of the localization of 5f electrons is the spin-orbit coupling and subsequent spin-lattice interaction that often leads to strongly anisotropic behavior. The unusual phase transition in UO2, for example, arises from interactions between quadrupole moments. On the other hand, in the monopnictides and monochalcogenides, the anisotropy is more difficult to understand, but probably involves an interaction between actinide and anion wave functions. A variety of neutron experiments, including form-factor studies, critical scattering and measurements of the elementary excitations have now been performed, and the conceptual picture emerging from these studies will be discussed

  15. Research on Actinides in Nuclear Fuel Cycles

    The electrochemical/spectroscopic integrated measurement system was designed and set up for spectro-electrochemical measurements of lanthanide and actinide ions in high temperature molten salt media. A compact electrochemical cell and electrode system was also developed for the minimization of reactants, and consequently minimization of radioactive waste generation. By applying these equipment, oxidation and reduction behavior of lanthanide and actinide ions in molten salt media have been made. Also, thermodynamic parameter values are determined by interpreting the results obtained from electrochemical measurements. Several lanthanide ions exhibited fluorescence properties in molten salt. Also, UV-VIS measurement provided the detailed information regarding the oxidation states of lanthanide and actinide ions in high temperature molten salt media

  16. Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms

    Kenneth L. Nash; Sue B. Clark; Gregg Lumetta

    2009-09-23

    With increased application of MOX fuels and longer burnup times for conventional fuels, higher concentrations of the transplutonium actinides Am and Cm (and even heavier species like Bk and Cf) will be produced. The half-lives of the Am isotopes are significantly longer than those of the most important long-lived, high specific activity lanthanides or the most common Cm, Bk and Cf isotopes, thus the greatest concern as regards long-term radiotoxicity. With the removal and transmutation of Am isotopes, radiation levels of high level wastes are reduced to near uranium mineral levels within less than 1000 years as opposed to the time-fram if they remain in the wastes.

  17. Actinide elements in aquatic and terrestrial environments

    Progress is reported on the following research projects: water-sediment interactions of U, Pu, Am, and Cm; relative availability of actinide elements from abiotic to aquatic biota; comparative uptake of transuranic elements by biota bordering Pond 3513; metabolic reduction of 239Np from Np(V) to Np(IV) in cotton rats; evaluation of hazards associated with transuranium releases to the biosphere; predicting Pu in bone; adsorption--solubility--complexation phenomena in actinide partitioning between sorbents and solution; comparative soil extraction data; and comparative plant uptake data

  18. Sequential analysis of selected actinides in urine

    The monitoring of personnel by urinalysis for suspected contamination by actinides necessitated the development and implementation of an analytical scheme that will separate and identify alpha emitting radionuclides of these elements. The present work deals with Pu, Am, and Th. These elements are separated from an ashed urine sample by means of coprecipitation and ion exchange techniques. The final analysis is carried out by electroplating the actinides and counting in a α-spectrometer. Mean recoveries of these elements from urine are: Pu 64%, Am 74% and Th 69%. (auth)

  19. Spin-Orbit Coupling in Actinide Cations

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.; Jensen, Hans Jorgen A.; Knecht, Stefan

    2012-09-01

    The limiting case of Russell-Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin-orbit splitting is large enough to cause a significantly reduced spin alignment. Novel concepts are used to explain the dependence of the spin alignment on the 5f shell occupation. We present evidence that the XPS of ionic actinide materials may provide direct information about the angular momentum coupling within the 5f shell.

  20. Spin-orbit coupling in actinide cations

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.; Jensen, Hans Jørgen Aa.; Knecht, Stefan

    2012-09-01

    The limiting case of Russell-Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin-orbit splitting is large enough to cause a significantly reduced spin alignment. Novel concepts are used to explain the dependence of the spin alignment on the 5f shell occupation. We present evidence that the XPS of ionic actinide materials may provide direct information about the angular momentum coupling within the 5f shell.

  1. Actinide and fission product separation and transmutation

    NONE

    1993-07-01

    The second international information exchange meeting on actinide and fission product separation and transmutation, took place in Argonne National Laboratory in Illinois United States, on 11-13 November 1992. The proceedings are presented in four sessions: Current strategic system of actinide and fission product separation and transmutation, progress in R and D on partitioning processes wet and dry, progress in R and D on transmutation and refinements of neutronic and other data, development of the fuel cycle processes fuel types and targets. (A.L.B.)

  2. Actinide phosphonate complexes in aqueous solutions

    Complexes formed by actinides with carboxylic acids, polycarboxylic acids, and aminopolycarboxylic acids play a central role in both the basic and process chemistry of the actinides. Recent studies of f-element complexes with phosphonic acid ligands indicate that new ligands incorporating doubly ionizable phosphonate groups (-PO3H2) have many properties which are unique chemically, and promise more efficient separation processes for waste cleanup and environmental restoration. Simple diphosphonate ligands form much stronger complexes than isostructural carboxylates, often exhibiting higher solubility as well. In this manuscript recent studies of the thermodynamics and kinetics of f-element complexation by 1,1 and 1,2 diphosphonic acid ligands are described

  3. Actinide and fission product separation and transmutation

    The second international information exchange meeting on actinide and fission product separation and transmutation, took place in Argonne National Laboratory in Illinois United States, on 11-13 November 1992. The proceedings are presented in four sessions: Current strategic system of actinide and fission product separation and transmutation, progress in R and D on partitioning processes wet and dry, progress in R and D on transmutation and refinements of neutronic and other data, development of the fuel cycle processes fuel types and targets. (A.L.B.)

  4. Static, Mixed-Array Total Evaporation for Improved Quantitation of Plutonium Minor Isotopes in Small Samples

    Stanley, F. E.; Byerly, Benjamin L.; Thomas, Mariam R.; Spencer, Khalil J.

    2016-03-01

    Actinide isotope measurements are a critical signature capability in the modern nuclear forensics "toolbox", especially when interrogating anthropogenic constituents in real-world scenarios. Unfortunately, established methodologies, such as traditional total evaporation via thermal ionization mass spectrometry, struggle to confidently measure low abundance isotope ratios (CRM-126a, and compared with traditional total evaporation methods.

  5. Static, Mixed-Array Total Evaporation for Improved Quantitation of Plutonium Minor Isotopes in Small Samples

    Stanley, F. E.; Byerly, Benjamin L.; Thomas, Mariam R.; Spencer, Khalil J.

    2016-06-01

    Actinide isotope measurements are a critical signature capability in the modern nuclear forensics "toolbox", especially when interrogating anthropogenic constituents in real-world scenarios. Unfortunately, established methodologies, such as traditional total evaporation via thermal ionization mass spectrometry, struggle to confidently measure low abundance isotope ratios (CRM-126a, and compared with traditional total evaporation methods.

  6. Isotope enrichment systems

    This invention provides a system in which both phases of the countercurrent contact isotope exchange concentration process are recycled continuously and an isotope depleted liquid phase substance thereof has its prior content of the desired isotope of hydrogen and/or oxygen replenished in an isotope regenerator by direct contact isotope exchange with a flow of steam from a source external to the concentrating process, whereby such replenished liquid serves as the feed liquid for the concentration process. As the supply of steam is gaseous, all problems incident to mineral solids in solution in liquid water are eliminated. As the elevated temperature corresponds to that of the steam, the isotope replenishment of the process feed liquid may be conducted without materially altering the characteristics of the steam for use as an energy source in any system

  7. RAPID DETERMINATION OF ACTINIDES IN URINE BY INDUCTIVELY-COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY: A HYBRID APPROACH

    Maxwell, S.; Jones, V.

    2009-05-27

    A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are split between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3 h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6 h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically greater than 90%, in contrast to other reported methods using flow injection separation techniques for urine samples where plutonium yields were 70-80%. This method allows measurement of both long-lived and short-lived actinide isotopes. 239Pu, 242Pu, 237Np, 243Am, 234U, 235U and 238U were measured by ICP-MS, while 236Pu, 238Pu, 239Pu, 241Am, 243Am and 244Cm were measured by alpha spectrometry. The method can also be adapted so that the separation of uranium isotopes for assay is not required, if uranium assay by direct dilution of the urine sample is preferred instead

  8. Chemical compatibility of HLW borosilicate glasses with actinides

    During liquid storage of HLLW the formation of actinide enriched sludges is being expected. Also during melting of HLW glasses an increase of top-to-bottom actinide concentrations can take place. Both effects have been studied. Besides, the vitrification of plutonium enriched wastes from Pu fuel element fabrication plants has been investigated with respect to an isolated vitrification process or a combined one with the HLLW. It is shown that the solidification of actinides from HLLW and actinide waste concentrates will set no principal problems. The leaching of actinides has been measured in salt brine at 230C and 1150C. (orig.)

  9. Actinide recycle in LMFBRs as a waste management alternative

    Beaman, S.L.

    1979-08-21

    A strategy of actinide burnup in fast reactor systems has been investigated as an approach for reducing the long term hazards and storage requirements of the actinide waste elements and their decay daughters. The actinide recycle studies also included plutonium burnup studies in the event that plutonium is no longer required as a fuel. Particular emphasis was placed upon the timing of the recycle program, the requirements for separability of the waste materials, and the impact of the actinides on the reactor operations and performance. It is concluded that actinide recycle and plutonium burnout are attractive alternative waste management concepts. 25 refs., 14 figs., 34 tabs.

  10. Actinide recycle in LMFBRs as a waste management alternative

    A strategy of actinide burnup in fast reactor systems has been investigated as an approach for reducing the long term hazards and storage requirements of the actinide waste elements and their decay daughters. The actinide recycle studies also included plutonium burnup studies in the event that plutonium is no longer required as a fuel. Particular emphasis was placed upon the timing of the recycle program, the requirements for separability of the waste materials, and the impact of the actinides on the reactor operations and performance. It is concluded that actinide recycle and plutonium burnout are attractive alternative waste management concepts. 25 refs., 14 figs., 34 tabs

  11. SRNL Development of Recovery Processes for Mark-18A Heavy Actinide Targets

    Allender, Jeffrey S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bridges, Nicholas J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Loftin, Bradley M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dunsmuir, Michael D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-14

    Savannah River National Laboratory (SRNL) and Oak Ridge National Laboratory (ORNL) are developing plans for the recovery of rare and unique isotopes contained within heavy-actinide target assemblies, specifically the Mark-18A. Mark-18A assemblies were irradiated in Savannah River Site (SRS) reactors in the 1970s under extremely high neutron-flux conditions and produced, virtually, the world's supply of plutonium-244, an isotope of key importance to high-precision actinide measurement and other scientific and nonproliferation uses; and curium highly enriched in heavy isotopes (e.g., curium-246 and curium-248). In 2015 and 2016, SRNL is pursuing tasks that would reduce program risk and budget requirements, including further characterization of unprocessed targets; engineering studies for the use of the SRNL Shielded Cells Facility (SCF) for recovery; and development of onsite and offsite shipping methods including a replacement for the heavy (70 ton) cask previously used for onsite transfer of irradiated items at SRS. A status update is provided for the characterization, including modeling using the Monte Carlo N-Particle Transport Code (MCNP); direct non-destructive assay measurements; and cask design.

  12. Treatment of actinide-containing organic waste

    A method has been developed for reducing the volume of organic wastes and recovering the actinide elements. The waste, together with gaseous oxygen (air) is introduced into a molten salt, preferably an alkali metal carbonate such as sodium carbonate. The bath is kept at 7500 - 10000C and 0.5 - 10 atm to thermally decompose and partially oxidize the waste, while substantially reducing its volume. The gaseous effluent, mainly carbon dioxide and water vapour, is vented to the atmosphere through a series of filters to remove trace amounts of actinide elements or particulate alkali metal salts. The remaining combustion products are entrained in the molten salt. Part of the molten salt-combustion product mixture is withdrawn and mixed with an aqueous medium. Insoluble combustion products are then removed from the aqueous medium and are leached with a mixture of hydrofluoric and nitric acids to solubilize the actinide elements. The actinide elements are easily recovered from the acid solution using conventional techniques. (DN)

  13. Trends in actinide processing at Hanford

    In 1989, the mission at the Hanford Site began a dramatic and sometimes painful transition. The days of production--as we used to know it--are over. Our mission officially has become waste management and environmental cleanup. This mission change didn't eliminate many jobs--in fact, budgets have grown dramatically to support the new mission. Most all of the same skilled crafts, engineers, and scientists are still required for the new mission. This change has not eliminated the need for actinide processing, but it has certainly changed the focus that our actinide chemists and process engineers have. The focus used to be on such things as increasing capacity, improving separations efficiency, and product purity. Minimizing waste had become a more important theme in recent years and it is still a very important concept in the waste management and environmental cleanup arena. However, at Hanford, a new set of words dominates the actinide process scene as we work to deal with actinides that still reside in a variety of forms at the Hanford Site. These words are repackage, stabilize, remove, store and dispose. Some key activities in each of these areas are described in this report

  14. Report of the panel on inhaled actinides

    Some topics discussed are as follows: assessment of risks to man of inhaling actinides; use of estimates for developing protection standards; epidemiology of lung cancer in exposed human populations; development of respiratory tract models; and effects in animals: dose- and effect-modifying factors

  15. Electronic Structure of the Actinide Metals

    Johansson, B.; Skriver, Hans Lomholt

    1982-01-01

    itinerant to localized 5f electron behaviour calculated to take place between plutonium and americium. From experimental data it is shown that the screening of deep core-holes is due to 5f electrons for the lighter actinide elements and 6d electrons for the heavier elements. A simplified model for the full...

  16. Actinide and fission product partitioning and transmutation

    The third international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Cadarache France, on 12-14 December 1994. The proceedings are presented in six sessions : an introduction session, the major programmes and international cooperation, the systems studies, the reactors fuels and targets, the chemistry and a last discussions session. (A.L.B.)

  17. Actinide and fission product partitioning and transmutation

    NONE

    1995-07-01

    The third international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Cadarache France, on 12-14 December 1994. The proceedings are presented in six sessions : an introduction session, the major programmes and international cooperation, the systems studies, the reactors fuels and targets, the chemistry and a last discussions session. (A.L.B.)

  18. Placental transfer of plutonium and other actinides

    The report is based on an extensive literature search. All data available from studies on placental transfer of plutonium and other actinides in man and animals have been collected and analysed, and the report presents the significant results as well as unresolved questions and knowledge gaps which may serve as a waypost to future research work. (orig./MG)

  19. Spin–orbit coupling in actinide cations

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.;

    2012-01-01

    The limiting case of Russell–Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin–orbit splitting is large enough to cause a significantly reduced...

  20. ACTINET: a European Network for Actinide Sciences

    Full text of publication follows: The research in Actinide sciences appear as a strategic issue for the future of nuclear systems. Sustainability issues are clearly in connection with the way actinide elements are managed (either addressing saving natural resource, or decreasing the radiotoxicity of the waste). The recent developments in the field of minor actinide P and T offer convincing indications of what could be possible options, possible future processes for the selective recovery of minor actinides. But they point out, too, some lacks in the basic understanding of key-issues (such as for instance the control An versus Ln selectivity, or solvation phenomena in organic phases). Such lacks could be real obstacles for an optimization of future processes, with new fuel compounds and facing new recycling strategies. This is why a large and sustainable work appears necessary, here in the field of basic actinide separative chemistry. And similar examples could be taken from other aspects of An science, for various applications (nuclear fuel or transmutation targets design, or migration issues,): future developments need a strong, enlarged, scientific basis. The Network ACTINET, established with the support of the European Commission, has the following objectives: - significantly improve the accessibility of the major actinide facilities to the European scientific community, and form a set of pooled facilities, as the corner-stone of a progressive integration process, - improve mobility between the member organisations, in particular between Academic Institutions and National Laboratories holding the pooled facilities, - merge part of the research programs conducted by the member institutions, and optimise the research programs and infrastructure policy via joint management procedures, - strengthen European excellence through a selection process of joint proposals, and reduce the fragmentation of the community by putting critical mass of resources and expertise on

  1. Overall assessment of actinide partitioning and transmutation for waste management purposes

    A program to establish the technical feasibility and incentives for partitioning (i.e., recovering) actinides from fuel cycle wastes and then transmuting them in power reactors to shorter-lived or stable nuclides has recently been concluded at the Oak Ridge National Laboratory. The feasibility was established by experimentally investigating the reduction that can be practicably achieved in the actinide content of the wastes sent to a geologic repository, and the incentives for implementing this concept were defined by determining the incremental costs, risks, and benefits. Eight US Department of Energy laboratories and three private companies participated in the program over its 3-year duration. A reference fuel cycle was chosen based on a self-generated plutonium recycle PWR, and chemical flowsheets based on solvent extraction and ion-exchange techniques were generated that have the potential to reduce actinides in fuel fabrication and reprocessing plant wastes to less than 0.25% of those in the spent fuel. Waste treatment facilities utilizing these flowsheets were designed conceptually, and their costs were estimated. Finally, the short-term (contemporary) risks from fuel cycle operations and long-term (future) risks from deep geologic disposal of the wastes were estimated for cases with and without partitioning and transmutation. It was concluded that, while both actinide partitioning from wastes and transmutation in power reactors appear to be feasible using currently identified and studied technology, implementation of this concept cannot be justified because of the small long-term benefits and substantially increased costs of the concept

  2. Library of Recommended Actinide Decay Data, 2011

    A major objective of the nuclear data programme within the IAEA is to devise and promote improvements in the quality of nuclear data used in science and technology. Work of this nature was performed by participants in an IAEA coordinated research project (CRP) formulated in 2005 to produce an updated decay data library of important actinides recommended for adoption in various nuclear applications. The specific objectives of this project were to improve the accuracy of heavy element and actinide decay data in order to: determine more accurately the effects of these recommended data on fission reactor fuel cycles; aid in improved assessments of nuclear waste management procedures; provide more reliable decay data for nuclear safeguards; assess with greater confidence the environmental impact of specific actinides and other heavy element radionuclides generated through their decay chains; and extend the scientific knowledge of actinide decay characteristics for nuclear physics research and non-energy applications. Some CRP participants were able to perform a number of highly precise measurements, based on the availability of suitable source materials, and systematic in depth evaluations of the requested decay data. These requested data consisted primarily of half-lives, and α, β-, EC/β+, Auger electron, conversion electron, X ray and γ ray energies and emission probabilities, all with uncertainties expressed at the 1σ confidence level. The IAEA established a CRP entitled Updated Decay Data Library for Actinides in mid-2005. During the course of discussions at the coordinated research meetings, the participants agreed to undertake work programmes of measurements and evaluations, to be completed by the end of 2010. The results of the evaluation studies undertaken by the CRP are presented in Annex I. Annexes II-V include descriptions of the sources of the evaluated decay data and each individual evaluation process in detail, as well as data files in the Evaluated

  3. Study of strontium extraction as cryptate complex in view to 102 element separation from the actinides

    In the present report is studied in detail the extraction of strontium, in tracer amounts, as cryptate and its separation from the lanthanides and transplutonium elements with a high degree of purification. Influence of different parameters: pH of the aqueous phase, cryptant concentration, counteranion concentration, nature of the solvent are investigated. It is intended to use this method to separate the 102 element from actinides in the study of the isotope 102 259 produced in irradiation of a curium 248 target by oxygen 18 ions

  4. Characterization and development of an active scintillating target for nuclear reaction studies on actinides

    This article presents the development of a new kind of active actinide target, based on organic liquid scintillators containing the dissolved isotope. Amongst many advantages one can mention the very high detection efficiency, the Pulse Shape Discrimination capability, the fast response allowing high count rates and good time resolution and the ease of fabrication. The response of this target to fission fragments has been studied. The discrimination of alpha, fission and proton recoil events is demonstrated. The alpha decay and fission detection efficiencies are simulated and compared to measurements. Finally the use of such a target in the context of fast neutron induced reactions is discussed.

  5. Effect of hydrogen isotope content on tensile flow behavior of Zr-2.5Nb pressure tube material between 25 and 300 °C

    Bind, A. K.; Sunil, S.; Singh, R. N.

    2016-08-01

    Tensile properties of autoclaved Zr-2.5Nb pressure tube material containing hydrogen isotope between 5 and 200 wppm were evaluated between 25 and 300 °C using specimens with its axis oriented along longitudinal direction of the tube. Analysis of tensile test results showed that both YS and UTS of this alloy decreased linearly with increasing test temperature. The uniform and total plastic strain decreased marginally with increase in test temperature. At all test temperatures, before necking tensile properties were unaffected by hydrogen isotope concentration whereas hydrogen isotope had clear effect on post-necking tensile properties especially at 25 and 100 °C. Post-necking ductility showed a transition behavior at 25 and 100 °C and it was able to capture the effect of hydride embrittlement in this material.

  6. Enhancing VVER annular proliferation resistance fuel with minor actinides

    Key aspects of the Global Nuclear Energy Partnership (GNEP) are to significantly advance the science and technology of nuclear energy systems and the Advanced Fuel Cycle (AFC) program. It consists of both innovative nuclear reactors and innovative research in separation and transmutation. To accomplish these goals, international cooperation is very important and public acceptance is crucial. The merits of nuclear energy are high-density energy, with low environmental impacts (i.e. almost zero greenhouse gas emission). Planned efforts involve near term and intermediate-term improvements in fuel utilization and recycling in current light water reactors (LWRs) as well as the longer-term development of new nuclear energy systems that offer much improved fuel utilization and proliferation resistance, along with continued advances in operational safety. The challenges are solving the energy needs of the world, protection against nuclear proliferation, the problem of nuclear waste, and the global environmental problem. To reduce spent fuel for storage and enhance the proliferation resistance for the intermediate-term, there are two major approaches (a) increase the discharged spent fuel burnup in the advanced LWR (Gen-III Plus), which not only can reduce the spent fuel for storage, but also increase the 238Pu and 240Pu isotopes ratio to enhance the proliferation resistance, and (b) use of transuranic nuclides (237Np and 241Am) in the high burnup fuel, which can drastically increase the proliferation resistance isotope ratio of 238Pu /Pu. For future advanced nuclear systems, the minor actinides (MA) are viewed more as a resource to be recycled, or transmuted to less hazardous and possibly more useful forms, rather than simply as a waste stream to be disposed of in expensive repository facilities. As a result, MAs play a much larger part in the design of advanced systems and fuel cycles, not only as additional sources of useful energy, but also as direct contributors to the

  7. An Ordinary Chondrite Impactor Composition for the Bosumtwi Impact Structure, Ghana, West Africa: Discussion of Siderophile Element Contents and Os and Cr Isotope Data

    Koeberl, Christian; Shukolyukov, Alex; Lugmair, Guenter

    2004-01-01

    Osmium isotope data had shown that Ivory Coast tektites contain an extraterrestrial component, but do not allow distinction between chondritic and iron meteorite contamination. PGE abundances of Ivory Coast tektites and impactites and target rocks from the Bosumtwi crater, the source crater of the Ivory Coast tektites, were all relatively high and did not allow to resolve the presence, or identify the nature, of the meteoritic component. However, Cr isotope analyses of an Ivory Coast tektite yielded a distinct 53Cr excess of 0.30+/-0.06, which indicates that the Bosumtwi impactor was an ordinary chondrite.

  8. Adulteration Identification of Commercial Honey with the C-4 Sugar Content of Negative Values by an Elemental Analyzer and Liquid Chromatography Coupled to Isotope Ratio Mass Spectroscopy.

    Dong, Hao; Luo, Donghui; Xian, Yanping; Luo, Haiying; Guo, Xindong; Li, Chao; Zhao, Mouming

    2016-04-27

    According to the AOAC 998.12 method, honey is considered to contain significant C-4 sugars with a C-4 sugar content of >7%, which are naturally identified as the adulteration. However, the authenticity of honey with a C-4 sugar content of authenticity of honey with a C-4 sugar content of authenticity identification of honey with a C-4 sugar content of <0%. PMID:27064147

  9. Synthesis of actinide nitrides, phosphides, sulfides and oxides

    Van Der Sluys, William G.; Burns, Carol J.; Smith, David C.

    1992-01-01

    A process of preparing an actinide compound of the formula An.sub.x Z.sub.y wherein An is an actinide metal atom selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, x is selected from the group consisting of one, two or three, Z is a main group element atom selected from the group consisting of nitrogen, phosphorus, oxygen and sulfur and y is selected from the group consisting of one, two, three or four, by admixing an actinide organometallic precursor wherein said actinide is selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, a suitable solvent and a protic Lewis base selected from the group consisting of ammonia, phosphine, hydrogen sulfide and water, at temperatures and for time sufficient to form an intermediate actinide complex, heating said intermediate actinide complex at temperatures and for time sufficient to form the actinide compound, and a process of depositing a thin film of such an actinide compound, e.g., uranium mononitride, by subliming an actinide organometallic precursor, e.g., a uranium amide precursor, in the presence of an effectgive amount of a protic Lewis base, e.g., ammonia, within a reactor at temperatures and for time sufficient to form a thin film of the actinide compound, are disclosed.

  10. Adventures in Actinide Chemistry: A Year of Exploring Uranium and Thorium in Los Alamos

    Pagano, Justin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-08

    The first part of this collection of slides is concerned with considerations when working with actinides. The topics discussed in the document as a whole are the following: Actinide chemistry vs. transition metal chemistry--tools we can use; New synthetic methods to obtain actinide hydrides; Actinide metallacycles: synthesis, structure, and properties; and Reactivity of actinide metallacycles.

  11. Adventures in Actinide Chemistry: A Year of Exploring Uranium and Thorium in Los Alamos

    The first part of this collection of slides is concerned with considerations when working with actinides. The topics discussed in the document as a whole are the following: Actinide chemistry vs. transition metal chemistry--tools we can use; New synthetic methods to obtain actinide hydrides; Actinide metallacycles: synthesis, structure, and properties; and Reactivity of actinide metallacycles.

  12. Boron and strontium isotopes in studying the high boron content of the alluvial aquifer of the Cecina River valley, Central Italy

    The Cecina River basin extends over 900 km2 in Western Tuscany and includes the Northern part of the Larderello geothermal field. In this work the isotopic composition and concentration of boron and strontium dissolved in ground water, in surface waters, and in bottom sediments were analysed

  13. Baleen as a biomonitor of mercury content and dietary history of North Atlantic Minke Whales (Balaenopetra acutorostrata): combining elemental and stable isotope approaches

    Baleen is an incrementally-growing tissue of balaenopteran whales which preserves relatively well over time in museums and some archeological sites, and, therefore might be useful for studies examining long-term changes of metal levels in whales. This study examined Hg and stable C and N isotopic composition of baleen plates of the North Atlantic minke whale (Balaenoptera acutorostrata), which continues to be a food source for people in Greenland and elsewhere. We compared the Hg levels and stable isotopes of major tissues (kidney, liver and muscle) with those of baleen plates to see whether baleen could be used as a biomonitor of variations of Hg intake and diet both between individuals and within individuals over time. Mercury was significantly correlated with concentrations in all tissues (kidney, liver and muscle). Stable C and N isotopes in baleen were generally similar to those of muscle, which reflects the recent (approximately one month) feeding of the whale, but in some individuals there were significant differences between baleen and muscle. Sectioning of baleen into 1 cm longitudinal increments showed that these differences were due to marked dietary shifts by some individuals over time that had been recorded in the baleen but were lost from the muscle record. Whole baleen C and N isotopes were better correlated with tissue Hg levels, suggesting that baleen may provide a more reliable indicator of long-term average diet, which in turn may be better related to Hg accumulation in tissues than the shorter-term diet record contained in muscle

  14. R and D for actinide partitioning and recovery of valuables from high level waste using radiotracers

    In the context of growing world population with rapidly increasing energy needs and the threat of global warming due to CO2 emission (caused by fossil fuel burning), the nuclear energy may be an attractive option particularly in the developing countries. Recycling of fuel is a unique feature of nuclear power technology which makes it a favourable choice with respect to conservation of energy resources. Steady growth of global fuel reprocessing activities (6000 tHM/annum) implies a vital role of separation science in developing efficient procedures for the separation and purification of actinides and in devising safe procedures for the management of nuclear waste arising at different stages of the PUREX process. High Level Waste (HLW) comprising of the concentrate of the raffinate of the co-extraction cycle (with over 95% of the total radioactivity produced in the burn up process in reactor) need to be isolated from the biosphere. There is a consensus among the waste management technologists that the safest route to achieve this, is to deposit it in a stable geological formation after it's immobilization in suitable glass/Synroc matrix. It ensures that any risk from exposure due to accidental intervention or natural disturbance is minimized. Risk perception is essentially due to the large radiological toxicity associated with alpha emitters like 237Np, 241Am, 243Am and 245Cm. Isotopes of Pu (left unrecovered) present in HLW also contribute towards radiological toxicity. In view of the high cost involved and the need for continuous surveillance, several countries are considering modifying their reprocessing schemes to partition (isolate) long-lived actinides from HLW. Since the volume of the actinide oxides (which retain major fraction of the radio toxicity of HLW) is significantly lower as compared to the other metal oxides present in HLW, such an approach is expected to reduce the cost of immobilization as well as of disposal (in geological repository) and

  15. Crystallo-chemistry of actinide nitrides (U1-yPuy)N and effect of impurities

    Investigations on actinide nitrides has been done in our Laboratories for Fast Breeder Reactors since the seventies and some properties are reported to show the interest for these fuels. Today, the actinide nitrides are reconsidered as possible fuels for the future fission reactors (GFR and LMFR selected by the international forum Generation IV). The results of new investigations on crystal structure of mixed mono-nitrides (U,Pu)N, and the effects of oxygen and carbon contaminations on this structure are presented. The cubic 'NaCl-fcc' type structure of actinide nitrides AnN with space group O5/h-Fm3m does not respect the 'Vegard law' model for the mixed nitrides (U1-yPuy)N. These nitrides are usually considered with strong metallic character associated with partial ionic bonding, but the ionic contribution in the An-N bonding determined in this work is very important and near 41.6% for UN and PuN. From results published on resistivity of mixed nitrides, the data on bonding must be also modified for partial covalence. This is in good agreement with the experimental lattice parameters which are not compatible with dominant metallic bonding. The numbers of bonding electrons in the nitrides (U1-yPuy)N are reevaluated and the low values proposed comparatively with those previously published confirm the strong ionic character with high concentration of An3+ ions. The solubility of oxygen and carbon in actinide nitrides (U1-yPuy)N are discussed from measurements on volume concentration of actinide oxide phase, total oxygen and carbon contents, and lattice parameter of nitrides. The oxygen solubility limit in UN is near 1000 ppm, with a lightly higher value of 1200 ppm for the mixed nitride (U0.8Pu0.2)N. The effects of oxygen or carbon atoms in the lattice of (U1-yPuy)N are analysed

  16. The analysis and handling concept of minor actinides of NPP’s waste by using Ads technology

    The contents of minor actinide elements (americium, neptunium and curium) on the spent fuel inventory from PWR operation of NPP have been calculated using Vista program. The calculation used parameters: enrichment 3.968%, power 1000 M We and burn-up is 60 M Wd/kg. The result of calculation showed that the arising of minor actinide elements on the spent fuel is 16.205 kg/year and 43.471 kg/year for PWR-UOX and PWR-MOX respectively. It is also discussed a concept of the use of ADS technology for transmuting the minor actinide elements contained in spent fuels. The result of the discussion showed that an ADS of 400 M Wth will serve 7 PWRs-UOX, and on the PWR system using UOX and MOX fuels an ADS will serve 3 PWRs. (author)

  17. Isotope and nuclear chemistry division. Annual report, FY 1987. Progress report, October 1986-September 1987

    This report describes progress in the major research and development programs carried out in FY 1987 by the Isotope and Nuclear Chemistry Division. The report includes articles on radiochemical weapons diagnostics and research and development; other unclassified weapons research; stable and radioactive isotope production and separation; chemical biology and nuclear medicine; element and isotope transport and fixation; actinide and transition metal chemistry; structural chemistry, spectroscopy, and applications; nuclear structure and reactions; irradiation facilities; advanced concepts and technology; and atmospheric chemistry

  18. Minor actinide transmutation on PWR burnable poison rods

    Highlights: • Key issues associated with MA transmutation are the appropriate loading pattern. • Commercial PWRs are the only choice to transmute MAs in large scale currently. • Considerable amount of MA can be loaded to PWR without disturbing keff markedly. • Loading MA to PWR burnable poison rods for transmutation is an optimal loading pattern. - Abstract: Minor actinides are the primary contributors to long term radiotoxicity in spent fuel. The majority of commercial reactors in operation in the world are PWRs, so to study the minor actinide transmutation characteristics in the PWRs and ultimately realize the successful minor actinide transmutation in PWRs are crucial problem in the area of the nuclear waste disposal. The key issues associated with the minor actinide transmutation are the appropriate loading patterns when introducing minor actinides to the PWR core. We study two different minor actinide transmutation materials loading patterns on the PWR burnable poison rods, one is to coat a thin layer of minor actinide in the water gap between the zircaloy cladding and the stainless steel which is filled with water, another one is that minor actinides substitute for burnable poison directly within burnable poison rods. Simulation calculation indicates that the two loading patterns can load approximately equivalent to 5–6 PWR annual minor actinide yields without disturbing the PWR keff markedly. The PWR keff can return criticality again by slightly reducing the boric acid concentration in the coolant of PWR or removing some burnable poison rods without coating the minor actinide transmutation materials from PWR core. In other words, loading minor actinide transmutation material to PWR does not consume extra neutron, minor actinide just consumes the neutrons which absorbed by the removed control poisons. Both minor actinide loading patterns are technically feasible; most importantly do not need to modify the configuration of the PWR core and

  19. Actinide and fission product separation and transmutation

    NONE

    1991-07-01

    The first international information exchange meeting on actinide and fission product separation and transmutation, took place in Mito in Japan, on 6-8 November 1990. It starts with a number of general overview papers to give us some broad perspectives. Following that it takes a look at some basic facts about physics and about the quantities of materials it is talking about. Then it proceeds to some specific aspects of partitioning, starting with evolution from today commercially applied processes and going on to other possibilities. At the end of the third session it takes a look at the significance of partitioning and transmutation of actinides before it embarks on two sessions on transmutation, first in reactors and second in accelerators. The last session is designed to throw back into the discussion the main points which need to be looked at when considering future work in this area. (A.L.B.)

  20. Interaction of actinide cations with synthetic polyelectrolytes

    The binding of Am+3, Th+4 and UO2+2 to polymaleic acid, polyethylenemaleic acid and polymethylvinylethermaleic acid has been measured by a solvent extraction technique at 250C and either 0.02 or 0.10 M ionic strength. The solutions were buffered over a pH range such that the percent of carboxylate groups ionized ranged from 25 to 74%. The binding was described by two constants, β1 and β2, which were evaluated after correction for complexation of the actinide cations by acetate and hydrolysis. For comparable degrees of ionization, all three polyelectrolytes showed similar binding strengths. In general, these results indicated that the binding of actinides to these synthetic polyelectrolytes is basically similar to that of natural polyelectrolytes such as humic and fulvic acids. (orig.)

  1. Actinide and fission product separation and transmutation

    The first international information exchange meeting on actinide and fission product separation and transmutation, took place in Mito in Japan, on 6-8 November 1990. It starts with a number of general overview papers to give us some broad perspectives. Following that it takes a look at some basic facts about physics and about the quantities of materials it is talking about. Then it proceeds to some specific aspects of partitioning, starting with evolution from today commercially applied processes and going on to other possibilities. At the end of the third session it takes a look at the significance of partitioning and transmutation of actinides before it embarks on two sessions on transmutation, first in reactors and second in accelerators. The last session is designed to throw back into the discussion the main points which need to be looked at when considering future work in this area. (A.L.B.)

  2. Method to determine actinide pollution in water

    This patent describes a process for measuring small amounts, of actinide pollution in fluidic samples by use of solid state track recording devices. It comprises: containing a sample to be tested, containing small amounts of less than 3E-12 Curies per cubic centimeter of actinide pollution, in a sample cell defining an internal chamber and having means for ingress and egress and means for establishing a fluidic sample therein, the sample cell being substantially transparent to thermal neutron radiation and the internal chamber defined therein being configured to constitute a fluidic sample therein as an asymptotic fluid fission source; positioning a solid state track recorder within the internal chamber defined by the sample cell, so that the solid state track recorder has a radiation viewing window through an asymptotic thickness of a fluidic sample contained in the sample cell; capturing at least an asymptotic amount of fluidic sample in the sample cell

  3. Microbial Transformations of Actinides and Other Radionuclides

    Francis,A.J.; Dodge, C. J.

    2009-01-07

    Microorganisms can affect the stability and mobility of the actinides and other radionuclides released from nuclear fuel cycle and from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution in the environment and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been extensively investigated, we have only limited information on the effects of microbial processes and biochemical mechanisms which affect the stability and mobility of radionuclides. The mechanisms of microbial transformations of the major and minor actinides U, Pu, Cm, Am, Np, the fission products and other radionuclides such as Ra, Tc, I, Cs, Sr, under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed.

  4. Actinides: from heavy fermions to plutonium metallurgy

    The actinide elements mark the emergence of 5f electrons. The f electrons possess sufficiently unusual characteristics that their participation in atomic binding often result in dramatic changes in properties. This provides an excellent opportunity to study the question of localization of electrons; a question that is paramount in predicting the physical and chemical properties of d and f electron transition metals. The transition region between localized (magnetic) and itinerant (often superconducting) behavior provides for many interesting phenomena such as structural instabilities (polymorphism), spin fluctuations, mixed valences, charge density waves, exceptional catalytic activity and hydrogen storage. This region offers most interesting behavior such as that exhibited by the actinide compounds UBe13 and UPt3. Both compounds are heavy-fermion superconductors in which both magnetic and superconducting behavior exist in the same electrons. The consequences of f-electron bonding (which appears greatest at Plutonium) show dramatic effects on phase stability, alloying behavior, phase transformations and mechanical behavior

  5. Comparison of actinides and fission products recycling scheme with the normal plutonium recycling scheme in fast reactors

    Salahuddin Asif

    2013-01-01

    Full Text Available Multiple recycling of actinides and non-volatile fission products in fast reactors through the dry re-fabrication/reprocessing atomics international reduction oxidation process has been studied as a possible way to reduce the long-term potential hazard of nuclear waste compared to that resulting from reprocessing in a wet PUREX process. Calculations have been made to compare the actinides and fission products recycling scheme with the normal plutonium recycling scheme in a fast reactor. For this purpose, the Karlsruhe version of isotope generation and depletion code, KORIGEN, has been modified accordingly. An entirely novel fission product yields library for fast reactors has been created which has replaced the old KORIGEN fission products library. For the purposes of this study, the standard 26 groups data set, KFKINR, developed at Forschungszentrum Karlsruhe, Germany, has been extended by the addition of the cross-sections of 13 important actinides and 68 most important fission products. It has been confirmed that these 68 fission products constitute about 95% of the total fission products yield and about 99.5% of the total absorption due to fission products in fast reactors. The amount of fissile material required to guarantee the criticality of the reactor during recycling schemes has also been investigated. Cumulative high active waste per ton of initial heavy metal is also calculated. Results show that the recycling of actinides and fission products in fast reactors through the atomics international reduction oxidation process results in a reduction of the potential hazard of radioactive waste.

  6. Preparation of actinide specimens for the US/UK joint experiment in the Dounreay Prototype Fast Reactor

    A joint research program involving the United States and the United Kingdom was initiated about four years ago for the purpose of studying the fuel behavior of higher actinides using in-core irradiation in the fast reactor at Dounreay, Scotland. Simultaneously, determination of integral cross sections of a wide variety of higher actinide isotopes (physics specimens) was proposed. Coincidental neutron flux and energy spectral measurements were to be made using vanadium encapsulated dosimetry materials in the immediate region of the fuel pellets and physics samples. The higher actinide samples chosen for the fuel study were 241Am and 244Cm in the forms of Am2O3, Cm2O3, and Am6Cm(RE)7O21, where (RE) represents a mixture of lanthanides. Milligram quantities of actinide oxides of 248Cm, 246Cm, 244Cm, 243Cm, 243Am, 241Am, 244Pu, 242Pu, 241Pu, 240Pu, 239Pu, 238Pu, 237Np, 238U, 236U, 235U, 234U, 233U, 232Th, 230Th, and 231Pa were encapsulated to obtain nuclear cross section and reaction rate data for these materials

  7. Actinide co-ordination and discrimination by human transferrin

    The design and evaluation of synthetic chelating agents which are specific for the actinide(IV) ions are described. The initial approach has been based on the biological and chemical similarities of Pu(IV) and Fe(III). In particular, using a philosophy influenced by naturally occurring ferric ion chelating agents, tetracatechoylamide ligands have been developed for the actinides. The test of the degree to which there was an actinide-specific complexing agent has been based on studies using Pu4+ as a biological contaminant. For a chelating agent to be able to sequester actinides effectively, it must remove actinides from actinide(IV)-protein complexes. The complexation chemistry of Th(IV)-transferrin system is described. The evidence suggests that, based on a size criterion, Th(IV) may be a poor biological model for Pu(IV) in some cases, with U(IV) being a somewhat better model. (author)

  8. Actinide Source Term Program, position paper. Revision 1

    The Actinide Source Term represents the quantity of actinides that could be mobilized within WIPP brines and could migrate with the brines away from the disposal room vicinity. This document presents the various proposed methods for estimating this source term, with a particular focus on defining these methods and evaluating the defensibility of the models for mobile actinide concentrations. The conclusions reached in this document are: the 92 PA open-quotes expert panelclose quotes model for mobile actinide concentrations is not defensible; and, although it is extremely conservative, the open-quotes inventory limitsclose quotes model is the only existing defensible model for the actinide source term. The model effort in progress, open-quotes chemical modeling of mobile actinide concentrationsclose quotes, supported by a laboratory effort that is also in progress, is designed to provide a reasonable description of the system and be scientifically realistic and supplant the open-quotes Inventory limitsclose quotes model

  9. Actinides reduction by recycling in a thermal reactor

    This work is directed towards the evaluation of an advanced nuclear fuel cycle in which radioactive actinides could be recycled to remove most of the radioactive material; firstly a production reference of actinides in standard nuclear fuel of uranium at the end of its burning in a BWR reactor is established, after a fuel containing plutonium is modeled to also calculate the actinides production in MOX fuel type. Also it proposes a design of fuel rod containing 6% of actinides in a matrix of uranium from the tails of enrichment, then four standard uranium fuel rods are replaced by actinides rods to evaluate the production and transmutation thereof, the same procedure was performed in the fuel type MOX and the end actinide reduction in the fuel was evaluated. (Author)

  10. Actinide and fission product partitioning and transmutation

    NONE

    1997-07-01

    The fourth international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Mito City in Japan, on 111-13 September 1996. The proceedings are presented in six sessions: the major programmes and international cooperation, the partitioning and transmutation programs, feasibility studies, particular separation processes, the accelerator driven transmutation, and the chemistry of the fuel cycle. (A.L.B.)

  11. The actinide waste problem in perspective

    The long lived alpha emitting actinide waste nuclides of transplutonium elements such as Np, Am, Cm etc (also called Byproduct Actinides or BPA for short) which are proposed to be disposed of as part of High Active Waste (HAW) in deep underground geological repositories has been a persistent source of concern to opponents and critics of nuclear fission energy. In this context the recent finding of the authors that each and every transuranium nuclide, without exception, can independently support a self sustaining chain reaction raises the important philosophical question: Is it justified to continue to refer to these nuclides as nuclear waste ? Our computations have revealed that the Ksub(eff) of an assembly of each of these nuclides increases linearly with the fissility parameter (Z2/A), its threshold value for Ksub(eff) to exceed unity being 34.1 for fissile (odd neutron) nuclides and 34.9 for fissible (even neutron) nuclides. In other words higher the (Z2/A) better is its performance as a fission reactor fuel. This finding suggests that the long lived actinide waste problem can be solved by separating all the actinide nuclides from the High Active Waste stream and recycling them back into any hard spectrum fission reactor. The studies strongly support the concept of partitioning-transmutation (p-t) revived with great enthusiasm in Japan under the banner of the OMEGA proposal. However it is found that there is no need to resort to any exotic devices such as proton accelerators or fusion reactor blankets for nuclear incineration. In the context of the 232Th/233U fuel cycle it is worth noting that the quantum of transuranium nuclides generated per se is smaller by several orders of magnitude as compared to that arising from 235U/238U bearing fuels. Thus on the whole it appears that in the thorium fuel cycle partitioning and recycle of byproduct nuclides would be a less cumbersome undertaking. (author). 26 refs., 6 figs., 3 tabs

  12. Actinide and fission product partitioning and transmutation

    The fourth international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Mito City in Japan, on 111-13 September 1996. The proceedings are presented in six sessions: the major programmes and international cooperation, the partitioning and transmutation programs, feasibility studies, particular separation processes, the accelerator driven transmutation, and the chemistry of the fuel cycle. (A.L.B.)

  13. SPECIFIC SEQUESTERING AGENTS FOR THE ACTINIDES

    Raymond, Kenneth N.; Smith, William L.; Weitl, Frederick L.; Durbin, Patricia W.; Jones, E.Sarah; Abu-Dari, Kamal; Sofen, Stephen R.; Cooper, Stephen R.

    1979-09-01

    This paper summarizes the current status of a continuing project directed toward the synthesis and characterization of chelating agents which are specific for actinide ions - especially Pu(IV) - using a biomimetic approach that relies on the observation that Pu(IV) and Fe(III) has marked similarities that include their biological transport and distribution in mammals. Since the naturally-occurring Fe(III) sequestering agents produced by microbes commonly contain hydroxamate and catecholate functional groups, these groups should complex the actinides very strongly and macrocyclic ligands incorporating these moieties are being prepared. We have reported the isolation and structure analysis of an isostructural series of tetrakis(catecholato) complexes with the general stoichiometry Na{sub 4}[M(C{sub 6}H{sub 4}O{sub 2}){sub 4}] • 21 H{sub 2}O (M = Th, U, Ce, Hf). These complexes are structural archetypes for the cavity that must be formed if an actinide-specific sequestering agent is to conform ideally to the coordination requirements of the central metal ion. The [M(cat){sub 4}]{sup 4-} complexes have the D{sub 2d} symmetry of the trigonal-faced dodecahedron.. The complexes Th [R'C(0)N(O)R]{sub 4} have been prepared where R = isopropyl and R' = t-butyl or neopentyl. The neopentyl derivative is also relatively close to an idealized D{sub 2d} dodecahedron, while the sterically more hindered t-butyl compound is distorted toward a cubic geometry. The synthesis of a series of 2, 3-dihydroxy-benzoyl amide derivatives of linear and cyclic tetraaza- and diazaalkanes is reported. Sulfonation of these compounds improves the metal complexation and in vivo removal of plutonium from test animals. These results substantially exceed the capabilities of compounds presently used for the therapeutic treatment of actinide contamination.

  14. The electrochemical properties of actinide amalgams

    Standard potentials are selected for actinides (An) and their amalgams. From the obtained results, energy characteristics are calculated and analyzed for alloy formation in An-Hg systems. It is found that solutions of the f-elements in mercury are very close in properties to amalgams of the alkali and alkaline-earth metals, except that, for the active Group III metals, the ion skeletons have a greater number of realizable charged states in the condensed phase

  15. In vitro removal of actinide (IV) ions

    Weitl, Frederick L.; Raymond, Kenneth N.

    1982-01-01

    A compound of the formula: ##STR1## wherein X is hydrogen or a conventional electron-withdrawing group, particularly --SO.sub.3 H or a salt thereof; n is 2, 3, or 4; m is 2, 3, or 4; and p is 2 or 3. The present compounds are useful as specific sequestering agents for actinide (IV) ions. Also described is a method for the 2,3-dihydroxybenzamidation of azaalkanes.

  16. Strength of Coriolis alignment in actinide nuclei

    Analysis of aligned angular momenta i/sub α/(ω) in different rotational bands extracted from experimental data with a linear spin term approx.BI in the formulas for E/sub rot/(I) reveal that, in actinide nuclei in the levels with modest spin I< or =23, i/sub α/(ω) usually is very small (< or approx. =0.7), i.e., is much smaller than in rare earth nuclei

  17. Thermodynamics and biogeochemistry of lanthanides and actinides

    Periodicity of changes in specific values of heat capacity and entropy of chemical elements, lanthanides, actinides, separating or transition elements, first of all, depending on their ordinal number, was considered. It is shown that entropy minima separate the chemical elements into light-weight and more heavy ones. The universal separation is fundamental, as it dictates the difference of the chemical elements not only in terms of thermodynamic, but also metallogenic, biogeochemical and physical properties, as well

  18. Thermal properties of minor actinide targets

    Staicu, Dragos; Somers, Joseph; FERNANDEZ CARRETERO Asuncion; KONINGS Rudy

    2014-01-01

    The thermal properties of minor actinides targets for the management of high level and long lived radioactive waste are investigated. The microstructure, thermal diffusivity and specific heat of (Pu,Am)O2, (Zr,Pu,Am)O2, (Zr,Y,Am)O2, (Zr,Y,Pu,Am)O2 and CERMETS with Mo matrix are characterised in order to assess the safety limits of these materials.

  19. Actinide behavior in a freshwater pond

    Long-term investigations of solution chemistry in an alkaline freshwater pond have revealed that actinide oxidation state behavior, particularly that of plutonium, is complex. The Pu(V,VI) fraction was predominant in solution, but it varied over the entire range reported from other natural aquatic environments, in this case, as a result of intrinsic biological and chemical cycles (redox and pH-dependent phenomena). A strong positive correlation between plutonium (Pu), but not uranium (U), and hydroxyl ion over the observation period, especially when both were known to be in higher oxidation states, was particularly notable. Coupled with other examples of divergent U and Pu behavior, this result suggests that Pu(V), or perhaps a mixture of Pu(V,VI), was the prevalent oxidation state in solution. Observations of trivalent actinide sorption behavior during an algal bloom, coupled with the association with a high-molecular weight (nominally 6000 to 10,000 mol wt) organic fraction in solution, indicate that solution-detritus cycling of organic carbon, in turn, may be the primary mechanism in amercium-curium (Am-Cm) cycling. Sorption by sedimentary materials appears to predominate over other factors controlling effective actinide solubility and may explain, at least partially, the absence of an expected strong positive correlation between carbonate and dissolved U. 49 references, 6 figures, 12 tables

  20. Analysis of optical properties of actinide dioxides

    Ionic calculations, symmetry considerations, and detailed analysis of reflectivity experiments have been used to identify general features of the band structure of actinide dioxides with a fluorite lattice. The ionic calculations adjust atomic energy levels by the electrostatic energies arising from long range electric fields of the ionic lattice; the labelling of high lying energy bands is determined by symmetry; experimental analysis includes the use of appropriate sum rules. A combination of these considerations enable a tentative band scheme to be constructed. It is suggested that there are filled valence bands (GAMMA15,GAMMA'25) originating in oxygen 2p-states and empty conduction bands (GAMMA1,GAMMA12,GAMMA'25) originating in actinide 7s and 6d states. The mean band gap (Penn gap) is of the order of 14 eV. The actinide f-electron states, which lie approximately 5 eV below the conduction bands, are taken to be localized - at least in UO2. (author)

  1. BWR Assembly Optimization for Minor Actinide Recycling

    The Primary objective of the proposed project is to apply and extend the latest advancements in LWR fuel management optimization to the design of advanced boiling water reactor (BWR) fuel assemblies specifically for the recycling of minor actinides (MAs). A top-level objective of the Advanced Fuel Cycle Systems Analysis program element of the DOE NERI program is to investigate spent fuel treatment and recycling options for current light water reactors (LWRs). Accordingly, this project targets to expand the traditional scope of nuclear fuel management optimization into the following two complementary specific objectives: (1) To develop a direct coupling between the pin-by-pin within-bundle loading control variables and core-wide (bundle-by-bundle) optimization objectives, (2) to extend the methodology developed to explicitly encompass control variables, objectives, and constraints designed to maximize minor actinide incineration in BWR bundles and cycles. The first specific objective is projected to 'uncover' dormant thermal margin made available by employing additional degrees of freedom within the optimization process, while the addition of minor actinides is expected to 'consume' some of the uncovered thermal margin. Therefore, a key underlying goal of this project is to effectively invest some of the uncovered thermal margin into achieving the primary objective.

  2. Geochemistry of the waters associated with the Cigar lake uranium deposit (Saskatchewan, (CA)) and their uranium and lead isotope contents as guides for prospecting

    The primary objective of this study is to understand the chemical evolution of the waters crossing the Cigar Lake (Saskatchewan, Canada) uranium ore deposit, then to investigate the behavior of the lead and uranium isotopes, and to test their use as guides in exploration. The underground waters around the Cigar Lake ore deposit were sampled by pumping boreholes or by air lifting. Isotopic analyses of U and Pb and chemical analyses of the major elements and of some trace elements (Ba, Ra, U) were completed. Based on these results, a model is proposed to explain the genesis and evolution of the waters, and also to account for the water-minerals equilibria. 37 refs., 8 figs., 4 tabs

  3. Ground-state electronic structure of actinide monocarbides and mononitrides

    Petit, Leon; Svane, Axel; Szotek, Z.;

    2009-01-01

    The self-interaction corrected local spin-density approximation is used to investigate the ground-state valency configuration of the actinide ions in the actinide monocarbides, AC (A=U,Np,Pu,Am,Cm), and the actinide mononitrides, AN. The electronic structure is characterized by a gradually...... the localization transition. The calculated valence electron densities of states are in good agreement with photoemission data....

  4. Successive change regularity of actinide properties with atomic number

    The development and achievements on chemistry of actinide elements are summarised. The relations of properties of actinides to their electronic configurations of valence electronic shells are discussed. Some anomalies of solid properties, the radius contraction, the stable state effect of f7n-orbits (n = 0, 1, 2) and the tetrad effect of oxidation states, etc., with atomic number (Z) are described. 31 figures appended show directly the successive change regularity of actinide properties with Z

  5. Study on remain actinides recovery in pyro reprocessing

    The spent fuel reprocessing by dry process called pyro reprocessing have been studied. Most of U, Pu and MA (minor actinides) from the spent fuel will be recovered and be fed back to the reactor as new fuel. Accumulation of remain actinides will be separated by extraction process with liquid cadmium solvent. The research was conducted by computer simulation to calculate the stage number required. The calculation's results showed on the 20 stages extractor more than 99% actinides can be separated. (author)

  6. The contribution of insect prey to the total nitrogen content of sundews (Drosera spp.) determined in situ by stable isotope analysis

    Millett, J.; Jones, R. I.; S. Waldron

    2003-01-01

    The contribution of insect prey to total N in the carnivorous plants, Drosera rotundifolia and D. intermedia, was quantified in situ and without any experimental manipulation using natural abundance stable isotope analysis. Samples of D. rotundifolia and D. intermedia, insects and noncarnivorous reference plants were collected from three contrasting locations across Britain. The proportion of Drosera nitrogen obtained from insect prey was calculated by a mixing model using δ15N values fro...

  7. Isotopic Biogeochemistry

    Hayes, J. M.

    1985-01-01

    An overview is provided of the biogeochemical research. The funding, productivity, personnel and facilities are reviewed. Some of the technical areas covered are: carbon isotopic records; isotopic studies of banded iron formations; isotope effects in microbial systems; studies of organic compounds in ancient sediments; and development in isotopic geochemistry and analysis.

  8. Isotopes as detectives in blood and orange juice

    The isotope content (Deuterium or Oxygen 18) allows one to distinguish between natural orange juice and rediluted concentrates. The isotope content of human blood or urine allows proves changes of location. (orig.)

  9. Search for a meteoritic component in drill cores from the Bosumtwi impact structure, Ghana: Platinum group element contents and osmium isotopic characteristics

    McDonald, Iain; Peucker-Ehrenbrink, Bernhard; Coney, Louise; Ferrière, Ludovic; Reimold, Wolf Uwe; Koeberl, Christian

    An attempt was made to detect a meteoritic component in both crater-fill (fallback) impact breccias and fallout suevites (outside the crater rim) at the Bosumtwi impact structure in Ghana. Thus far, the only clear indication for an extraterrestrial component related to this structure has been the discovery of a meteoritic signature in Ivory Coast tektites, which formed during the Bosumtwi impact event. Earlier work at Bosumtwi indicated unusually high levels of elements that are commonly used for the identification of meteoritic contamination (i.e., siderophile elements, including the platinum group elements [PGE]) in both target rocks and impact breccias from surface exposures around the crater structure, which does not allow unambiguous verification of an extraterrestrial signature. The present work, involving PGE abundance determinations and Os isotope measurements on drill core samples from inside and outside the crater rim, arrives at the same conclusion. Despite the potential of the Os isotope system to detect even small amounts of extraterrestrial contribution, the wide range in PGE concentrations and Os isotope composition observed in the target rocks makes the interpretation of unradiogenic, high-concentration samples as an impact signature ambiguous.

  10. Actinides AMS at CIRCE and 236U and Pu measurements of structural and environmental samples from in and around a mothballed nuclear power plant

    De Cesare, M.; Fifield, L. K.; Sabbarese, C.; Tims, S. G.; De Cesare, N.; D'Onofrio, A.; D'Arco, A.; Esposito, A. M.; Petraglia, A.; Roca, V.; Terrasi, F.

    2013-01-01

    Accelerator mass spectrometry (AMS) is presently the most sensitive technique for the measurement of long-lived actinides, e.g. 236U and 239Pu. A new actinide line is in operation at the Center for Isotopic Research on Cultural and Environmental heritage (CIRCE) in Caserta, Italy. Using the actinide line a uranium mass sensitivity of around 4 μg has been reached measuring with a 16-strip silicon detector, and a 239Pu background level of below 0.1 fg has been obtained. In this work we also discuss preliminary results for environmental and structural samples from in and around the Garigliano nuclear power plant (GNPP), presently in the decommissioning phase. Measurements on environmental samples from the vicinity of the plant allow the assessment of contamination, if any, over the years. Measurements of structural samples from the plant are relevant to the optimization of the decommissioning program for the GNPP.

  11. Actinides AMS at CIRCE and 236U and Pu measurements of structural and environmental samples from in and around a mothballed nuclear power plant

    Accelerator mass spectrometry (AMS) is presently the most sensitive technique for the measurement of long-lived actinides, e.g. 236U and 239Pu. A new actinide line is in operation at the Center for Isotopic Research on Cultural and Environmental heritage (CIRCE) in Caserta, Italy. Using the actinide line a uranium mass sensitivity of around 4 μg has been reached measuring with a 16-strip silicon detector, and a 239Pu background level of below 0.1 fg has been obtained. In this work we also discuss preliminary results for environmental and structural samples from in and around the Garigliano nuclear power plant (GNPP), presently in the decommissioning phase. Measurements on environmental samples from the vicinity of the plant allow the assessment of contamination, if any, over the years. Measurements of structural samples from the plant are relevant to the optimization of the decommissioning program for the GNPP.

  12. Fabrication and characterisation of composite targets for the transmutation of actinides

    Transmutation of transuranic elements separated from spent fuel is a way to reduce the toxicity of long-lived nuclides in the waste before disposal. Plutonium and the minor actinides (MA) are reintroduced into the fuel cycle for further irradiation and incineration. Currently CERMET fuel forms, in which a ceramic actinide is dispersed in a matrix, are considered for MA transmutation. In a first step, PuO2 beads are produced by a sol gel method in which a Pu nitrate solution is converted to solid, dust-free, particles. These porous beads are then infiltrated with an americium nitrate solution to the incipient wetness point and calcined to give the (PuAm)O2 beads, which are blended with a metal matrix and compacted and sintered to form the final fuel pellet. The matrix used is molybdenum due to its high thermal conductivity and low neutron capture cross section, if it is enriched in 92Mo. In this work, optimization of the bead porosity is investigated to achieve a higher Am content by infiltration. Addition of carbon to the mother solution in the sol gel step increases the bead porosity but it also changes both bead and final fuel pellet microstructure. A surrogate fuel, with cerium simulating the actinides has been fabricated and its mechanical stability and bead characteristics investigated as a function of carbon content and thermal treatment. The characterization of the surrogate fuel by ceramography, density, porosity, bead-quality, etc., is a necessary step in the process optimization, to be transferred to the production of the actinide samples. This process is now at an advanced stage and is being used for the production of fuels for irradiation tests in the Phenix (Futurix) and HFR-Petten (HELIOS) reactors. In parallel, studies on the dissolution of the fuel pellets, with the aim of dissolving the Mo-matrix while keeping the CeO2 beads intact, have been initiated. Thus, Mo can be recycled for further fuel fabrication either from production scraps or from the

  13. Bidentate organophosphorus solvent extraction process for actinide recovery and partition

    Schulz, Wallace W.

    1976-01-01

    A liquid-liquid extraction process for the recovery and partitioning of actinide values from acidic nuclear waste aqueous solutions, the actinide values including trivalent, tetravalent and hexavalent oxidation states is provided and includes the steps of contacting the aqueous solution with a bidentate organophosphorous extractant to extract essentially all of the actinide values into the organic phase. Thereafter the respective actinide fractions are selectively partitioned into separate aqueous solutions by contact with dilute nitric or nitric-hydrofluoric acid solutions. The hexavalent uranium is finally removed from the organic phase by contact with a dilute sodium carbonate solution.

  14. Certification of the Cu and Cd amount contents in artificial food digest using isotope dilution inductively coupled plasma mass spectrometry for Pilot Study 13 of the Comite Consultatif pour la Quantite de Matiere

    The Comite Consultatif pour la Quantite de Matiere (CCQM) launched the Pilot Study 13, an interlaboratory comparison between the metrological organizations worldwide on the determination of Ca, Cu and Cd in artificial food digests. These samples (available in 7% HNO3 and with a salinity evaluated around 370 mg kg-1, including approx. 30 mg Na kg-1) were prepared by gravimetrical mixing, and thus reference values traceable to the Kg for the three elements were available eventually. This paper describes the contribution of IRMM for the certification of the Cu and the Cd amount contents. The analytical protocol developed was based on isotope dilution associated to inductively coupled plasma mass spectrometry (ID-ICP-MS). The Cu measurements required 125-fold dilution of the initial sample solution. An interference of 23Na40Ar+ on 63Cu+ was identified but, since the ratio between both species was over 1000, it was successfully overcome by the calculation of a correction factor for its effect on the Cu amount content directly. Dilution of the sample was not possible for Cd only present at the low ng g-1 level. Up to 1% difference was observed on Cd isotope ratio results between measurements performed directly or after matrix separation. This is rarely shown. As similar results could be obtained either way after the necessary corrections, the direct measurements approach associated to a correction for mass discrimination effects using the CCQM-P13 sample itself (and the IUPAC table values as reference for the natural Cd isotopic composition) was preferred as it was the easiest. SI traceable values were obtained for Cu and Cd with less than 1 and 1.5% combined uncertainty, respectively (6 995±55 (k=2) nmol kg-1 and 45.53±0.64 (k=2) nmol kg-1). The excellent agreement between these results and the reference values (less than 0.6 and 0.08% difference) further validated the analytical protocols developed

  15. Preparations and mechanism of hydrolysis of ((8)annulene)actinide compounds. [Uranocene

    Moore, R.M. Jr.

    1985-07-01

    The mechanism of hydrolysis for bis(8)annulene actinide and lanthanide complexes has been studied in detail. The uranium complex, uranocene, decomposes with good pseudo-first order kinetics (in uranocene) in 1 M degassed solutions of H/sub 2/O in THF. Decomposition of a series of aryl-substituted uranocenes demonstrates that the hydrolysis rate is dependent on the electronic nature of the substituent (Hammett rho value = 2.1, r/sup 2/ = 0.999), with electron-withdrawing groups increasing the rate. When D/sub 2/O is substituted for H/sub 2/O, kinetic isotope effects of 8 to 14 are found for a variety of substituted uranocenes. These results suggest a pre-equilibrium involving approach of a water molecule to the central metal, followed by rate determining proton transfer to the eight membered ring and rapid decomposition to products. Each of the four protonations of the complex has a significant isotope effect. The product ratio of cyclooctatriene isomers formed in the hydrolysis varies, depending on the central metal of the complex. However, the general mechanism of hydrolysis, established for uranocene, can be extended to the hydrolysis and alcoholysis of all the (8)annulene complexes of the lanthanides and actinides.

  16. Preparations and mechanism of hydrolysis of ([8]annulene)actinide compounds

    The mechanism of hydrolysis for bis[8]annulene actinide and lanthanide complexes has been studied in detail. The uranium complex, uranocene, decomposes with good pseudo-first order kinetics (in uranocene) in 1 M degassed solutions of H2O in THF. Decomposition of a series of aryl-substituted uranocenes demonstrates that the hydrolysis rate is dependent on the electronic nature of the substituent (Hammett rho value = 2.1, r2 = 0.999), with electron-withdrawing groups increasing the rate. When D2O is substituted for H2O, kinetic isotope effects of 8 to 14 are found for a variety of substituted uranocenes. These results suggest a pre-equilibrium involving approach of a water molecule to the central metal, followed by rate determining proton transfer to the eight membered ring and rapid decomposition to products. Each of the four protonations of the complex has a significant isotope effect. The product ratio of cyclooctatriene isomers formed in the hydrolysis varies, depending on the central metal of the complex. However, the general mechanism of hydrolysis, established for uranocene, can be extended to the hydrolysis and alcoholysis of all the [8]annulene complexes of the lanthanides and actinides

  17. Selection of Isotopes and Elements for Fuel Cycle Analysis

    Steven J. Piet

    2009-04-01

    Fuel cycle system analysis simulations examine how the selection among fuel cycle options for reactors, fuel, separation, and waste management impact uranium ore utilization, waste masses and volumes, radiotoxicity, heat to geologic repositories, isotope-dependent proliferation resistance measures, and so forth. Previously, such simulations have tended to track only a few actinide and fission product isotopes, those that have been identified as important to a few criteria from the standpoint of recycled material or waste, taken as a whole. After accounting for such isotopes, the residual mass is often characterized as “fission product other” or “actinide other”. However, detailed assessment of separation and waste management options now require identification of key isotopes and residual mass for Group 1A/2A elements (Rb, Cs, Sr, Ba), inert gases (Kr, Xe), halogens (Br, I), lanthanides, transition metals, transuranic (TRU), uranium, actinide decay products. The paper explains the rationale for a list of 81 isotopes and chemical elements to better support separation and waste management assessment in dynamic system analysis models such as Verifiable Fuel Cycle Simulation (VISION)

  18. Advanced Aqueous Separation Systems for Actinide Partitioning

    Nash, Ken [Washington State Univ., Pullman, WA (United States); Martin, Leigh [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lumetta, Gregg [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-02

    One of the most challenging aspects of advanced processing of used nuclear fuel is the separation of transplutonium actinides from fission product lanthanides. This separation is essential if actinide transmutation options are to be pursued in advanced fuel cycles, as lanthanides compete with actinides for neutrons in both thermal and fast reactors, thus limiting efficiency. The separation is difficult because the chemistry of Am3+ and Cm3+ is nearly identical to that of the trivalent lanthanides (Ln3+). The prior literature teaches that two approaches offer the greatest probability of devising a successful group separation process based on aqueous processes: 1) the application of complexing agents containing ligand donor atoms that are softer than oxygen (N, S, Cl-) or 2) changing the oxidation state of Am to the IV, V, or VI state to increase the essential differences between Am and lanthanide chemistry (an approach utilized in the PUREX process to selectively remove Pu4+ and UO22+ from fission products). The latter approach offers the additional benefit of enabling a separation of Am from Cm, as Cm(III) is resistant to oxidation and so can easily be made to follow the lanthanides. The fundamental limitations of these approaches are that 1) the soft(er) donor atoms that interact more strongly with actinide cations than lanthanides form substantially weaker bonds than oxygen atoms, thus necessitating modification of extraction conditions for adequate phase transfer efficiency, 2) soft donor reagents have been seen to suffer slow phase transfer kinetics and hydro-/radiolytic stability limitations and 3) the upper oxidation states of Am are all moderately strong oxidants, hence of only transient stability in media representative of conventional aqueous separations systems. There are examples in the literature of both approaches having been described. However, it is not clear at present that any extant process is sufficiently robust for application at the scale

  19. Programme and Abstracts. 38. Journees des Actinides together with the 7. School on the Physics and Chemistry of the Actinides

    Journees des Actinides (JdA) is a traditional informal actinide forum, including physics, chemistry, and materials research. It regularly brings together experts from fields involved, taking place in a very informal way, emphasizing exchanges and discussions on current issues in actinide science. At the 38th JdA (10-15 April 2008; Wroclaw, Poland) scientific communications on the following topics on physics and chemistry of the actinides were presented: (a) inorganic and organometallic chemistry; (b) strongly correlated behaviour, superconductivity, quantum criticality; (c) materials science; (d) theory, electronic structure; (e) nuclear fuel cycle, environment

  20. The effects of actinide separation on the radiological consequences of disposal of high-level radioactive waste on the ocean bed

    One option in the management of high-level radioactive wastes is to separate the actinides prior to vitrification and disposal. This option is examined in the context of disposal of high-level wastes on the deep ocean bed. The initial quantity of waste corresponds to the generation of 1000 GW(e)y of nuclear energy, and the actinide-separation process is assumed to remove 99% of all elements of atomic number greater than that of actinium. The models used to describe the dispersion of activity from a single disposal site on the bed of the Atlantic Ocean represent both local dispersion and long-term mixing. Collective doses and doses to individuals are calculated for six potential pathways: ingestion of fish, crustacea, molluscs, plankton and seaweed, and external irradiation from contaminated beach sediments. The period from 400 to 1,000,000 years after disposal is considered. The potential radiological impact from disposal of high-level waste without separation of actinides on the ocean bed arises from the actinides; isotopes of americium, neptunium and plutonium give the highest doses. Actinide separation would reduce these doses in proportion to the effectiveness of the separation process, until doses become determined by fission products rather than actinides: the achievable dose reduction would be a factor of approximately a hundred, or less for certain pathways. This reduction applies only to doses to the public from waste disposal: no account was taken of doses arising from the separation process itself or from the management of the separated actinides. The results of the assessment are contrasted with those of similar studies based on toxicity indices. Major deficiencies are identified in the use of toxicity indices as a basis for decision-making. (author)

  1. Actinide transmutation using inert matrix fuels versus recycle in a low conversion fast burner reactor

    Reducing the disposal burden of the long lived radioisotopes that are contained within spent uranium oxide fuel is essential for ensuring the sustainability of nuclear power. Because of their non-fertile matrices, inert matrix fuels (IMFs) could allow light-water reactors to achieve a significant burn down of plutonium and minor actinides that are that are currently produced as a byproduct of operating light-water reactors. However, the extent to which this is possible is not yet fully understood. We consider a ZrO2 based IMF with a high transuranic loading and show that the neutron fluence (and the subsequent fuel residence time required to achieve it) present a practical limit for the achievable actinide burnup. The accumulation of transuranics in spent uranium oxide fuel is a major obstacle for the sustainability of nuclear power. While commercial light-water reactors (LWR's) produce these isotopes, they can be used to transmute them. At present, the only viable option for doing this is to partly fuel reactors with mixed oxide fuel (MOX) made using recycled plutonium. However, because of parasitic neutron capture in the uranium matrix of MOX, considerable plutonium and minor actinides are also bred as the fuel is burned. A better option is to entrain the recycled isotopes in a non-fertile matrix such as ZrO2. Inert matrices such as these were originally envisioned for burning plutonium from dismantled nuclear weapons [1]. However, because they achieve a conversion ratio of zero, they have also been considered as a better alternative to MOX [2-6]. Plutonium and minor actinides dominate the long term heat and radiological outputs from spent nuclear fuel. Recent work has shown that that IMFs can be used to reduce these outputs by at least a factor of four, on a per unit of energy generated basis [6]. The degree of reduction is strongly dependent on IMF burnup. In principle, complete transmutation of the transuranics could be achieved though this would require an

  2. Trace analysis of actinides in the environment using resonance ionization mass spectrometry; Spurenanalyse von Aktiniden in der Umwelt mittels Resonanzionisations-Massenspektrometrie

    Raeder, Sebastian

    2011-04-12

    In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10{sup 4}-10{sup 5} atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope {sup 236}U a detection limit down to 10{sup -9} for the isotope ratio N ({sup 236}U)/N ({sup 238}U) could be determined.

  3. Sediment source detection by stable isotope analysis, carbon and nitrogen content and CSSI in a small river of the Swiss Plateau

    SchindlerWildhaber, Yael; Alewell, Christine; Birkholz, Axel

    2014-05-01

    Suspended sediment (SS) and organic matter in rivers can harm the fauna by affecting health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C) and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the temporal and spatial sources of SS. We determined compound specific stable carbon isotopes (CSSI) in fatty acids of possible sediment source areas to the stream in addition and compared them to SS from selected high flow and low flow events. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to an increase in sediment delivery from pasture and arable land downstream of the river. While the major sources of SS are pasture and arable land during base flow conditions, SS from forest soils increased during heavy rain events and warmer winter periods most likely due to snow melt which triggered erosion. Preliminary results of CSSI analysis of sediment source areas and comparison to SS of selected events indicate that differences in d13C values of individual fatty acids are too small to differentiate unambiguously between sediment sources.

  4. Isotope and Nuclear Chemistry Division annual report, FY 1984

    This report describes progress in the major research and development programs carried out in FY 1984 by the Isotope and Nuclear Chemistry Division. It covers radiochemical diagnostics of weapons tests; weapons radiochemical diagnostics research and development; other unclassified weapons research; stable and radioactive isotope production, separation, and applications (including biomedical applications); element and isotope transport and fixation; actinide and transition metal chemistry; structural chemistry, spectroscopy, and applications; nuclear structure and reactions; irradiation facilities; advanced analytical techniques: development and applications; atmospheric chemistry and transport; and earth and planetary processes. 287 refs

  5. Isotope and Nuclear Chemistry Division annual report, FY 1983

    Heiken, J.H.; Lindberg, H.A. (eds.)

    1984-05-01

    This report describes progress in the major research and development programs carried out in FY 1983 by the Isotope and Nuclear Chemistry Division. It covers radiochemical diagnostics of weapons tests; weapons radiochemical diagnostics research and development; other unclassified weapons research; stable and radioactive isotope production, separation, and applications (including biomedical applications); element and isotope transport and fixation; actinide and transition metal chemistry; structural chemistry, spectroscopy, and applications; nuclear structure and reactions; irradiation facilities; advanced analytical techniques; development and applications; atmospheric chemistry and transport; and earth and planetary processes.

  6. Isotope and Nuclear Chemistry Division annual report, FY 1983

    This report describes progress in the major research and development programs carried out in FY 1983 by the Isotope and Nuclear Chemistry Division. It covers radiochemical diagnostics of weapons tests; weapons radiochemical diagnostics research and development; other unclassified weapons research; stable and radioactive isotope production, separation, and applications (including biomedical applications); element and isotope transport and fixation; actinide and transition metal chemistry; structural chemistry, spectroscopy, and applications; nuclear structure and reactions; irradiation facilities; advanced analytical techniques; development and applications; atmospheric chemistry and transport; and earth and planetary processes

  7. Evolution of Silurian and Devonian sedimentary environments in the Prague basin: evidence from isotopic compositions of carbon and oxygen and trace element contents in brachiopod shells

    Hladíková, J.; Hladil, Jindřich; Košler, J.; Jačková, I.

    Frankfurt am Main : European Palaeontological Association, 2000 - (Oschmann, W.; Steininger, F.; Fürsich, F.), s. 43- 45+ 1 nečíslovaná [European Palaeontological Association Workshop 2000 - Biomarkes and Stable Isotopes in Palaeontology. Frankfurt am Main (DE), 30.06.2000-02.07.2000] R&D Projects: GA ČR GA205/98/0454 Grant ostatní: XX(XX) IGCP386; XX(XC) IGCP421 Institutional research plan: CEZ:AV0Z3013912 Subject RIV: DB - Geology ; Mineralogy

  8. Decay analysis of pre-actinide and trans-actinide nuclei formed using various projectiles on a 197Au target at ECN*=60 MeV

    Grover, Neha; Kaur, Gurvinder; Sharma, Manoj K.

    2016-01-01

    The collective clusterization approach of the dynamical cluster decay model (DCM) has been applied to study the decay of odd mass nuclei 223Pa*, 215Fr*, 227Np*, and 233Am*, which are formed in heavy-ion-induced reactions. The aim of this study is to investigate the decay pattern and related behavior of these heavy mass nuclei formed in four distinct reactions involving different projectiles (with mass A =18 -36 ) induced on 197Au target nucleus. Further, in order to analyze the role of deformations, the calculations have been done by considering spherical choice of fragmentation as well as with inclusion of quadrupole (β2) deformation. For the heavy mass region, with fission being the dominant decay mode, an attempt has been made to investigate the effect of projectile mass in reference to fission decay patterns of the pre-actinide 215Fr* nucleus and the trans-actinide nuclei 227Np* 223Pa*, 223Am* and formed at common excitation energy, ECN*=60 MeV . Besides this, the shell closure effects and the role of orientation have been explored, which suggest the presence of a noncompound nucleus process such as quasifission (QF) for the odd mass nuclei under consideration. For both the compound nucleus and the noncompound nucleus processes, the results obtained using DCM are found to have nice agreement with experimental observations. The isotopic and isobaric analysis is also worked out so as to have a comprehensive idea about the dynamics involved.

  9. Abrupt Change Analyses of Oxygen, Carbon Isotope Values and Sr Contents in a Stalagmite Retrieved from Songjia Cave, NE Sichuan%大滁城人居环境适宜性研究

    李军利; 徐松南; 李建梅; 潘静

    2012-01-01

    以1km×1km栅格为基本单元,选取交通路网指数、水域指数、学校指数、居住影响力指数与地被指数等影响因子,运用GIS技术建立大滁城人居环境指数模型,定量研究大滁城规划区人居环境的适宜程度及其空间规律性。结果表明:大滁城人居环境指数呈现由中心区域向周边地区递减的趋势;人居环境指数与人口密度有较好的相关性,二者的一次拟合度R2=0.8361。一般适宜以上的地区132km2,接近大滁城面积的2.96%,相应的人口占大滁城8.75%,其中3.3%的人口聚集在0.78%人居环境高度适宜和比较适宜地区;临界适宜地区698km2,占大滁城面积的15.69%,人口39.33万;适宜性相对较差的地区3619km2,人口108.91万,占大滁城总面积的81.35%。%We analyze the abrupt changes of oxygen, carbon isotope values and Sr contents in stalagmite S J3 retrieved from Song:jia Cave, Central China. Some conclusions are given below : ( 1 ) Oxygen isotope values record the transition from Last Glacial Maximum to Heinrich Event One period;(2) Carbon isotope values record the transition from H1 cold period to BoilingAllerod warm period ; ( 3 ) The correlation between Carbon isotope values and Sr contents indicate that the local East Asian summer monsoon were in - phase with the winter monsoon during 19.8 - 15.3ka while out of phase during 15.3 - 14.8ka. It' s obvious that stalagmite S J3 records the palaeoclimate changes between colddry and warm wet conditions while different climate proxies were dissimilar in sensitivities with regard to climate changes.

  10. Comparative study of accelerator driven system (ADS) of different transmutation scenarios for actinides in advanced nuclear fuel cycles

    The full text follows. In recent years transmutation has raised as a complementary option to solve the problem of the long-lived radioactive waste produced in nuclear power plants. The main advantages expected from transmutation are the reduction in volume of the high level waste and a significant decrease in the long-term radiotoxicity inventory, with a probable impact in the final costs and potential risks of the geological repository. This paper will describe the evaluation of different systems proposed for actinide transmutation, their integration in the waste management process, their viability, performances and limitations. Particular attention is taking of comparing transmutation scenarios where the actinides are transmuted inside fertile (U, Th) or inert matrix. This study has been supported by ENRESA inside the CIEMAT-ENRESA collaboration for the study of long-lived isotope transmutation. (authors)

  11. Synergistic extraction of actinides : Part I. Hexa-and pentavalent actinides

    A detailed discussion on the reported literature on the synergistic extraction of hexa- and pentavalent actinide ions, by different combinations of extractants and from different aqueous media, is presented. Structural aspects of the various complexes involved in synergism also are reviewed. A short account of the applications based on synergistic extraction is also given. (author)

  12. Extraction of actinides and lanthanides by calixarenes CMPO. Possibility to separate actinides from lanthanides (Calixpart project)

    The CALIXPART project accepted by the European Community within the framework of the 5 PCRD, relates to the 'selective extraction of minor actinides from H.A. liquid waste by organized matrices'. The objective of this new project is the selective extraction in only one step of minor actinides from a solution of fission products including lanthanides. This separation will be investigated through two strategies: - In the first one, macrocycles will be grafted with ligands containing nitrogen or sulphur which are able to discriminate actinides from lanthanides, but generally present very low distribution coefficients in strongly acidic solutions. Following the example of calixarenes CMPO, the grafting of these ligands on macrocyclic supports should increase the distribution coefficients, and thus allow to use these extractants at nitric acid concentrations up to 3 M. The nitrogen or sulphur ligands are not necessarily selective with respect to the other fission products, and the macrocyclic structure should also afford this necessary selectivity if one wishes to operate in a single step. Once americium and curium separated, the difference in size between both cations is undoubtedly sufficient to make it possible to separate them at the stripping stage. - The second strategy considered is the introduction of two types of ligands (hard and soft) on a macrocyclic structure, the first ensuring the extraction of lanthanides and trivalent actinides, the seconds bringing discrimination between these two groups of cations. (author)

  13. Solubility of actinides and surrogates in nuclear glasses

    The nuclear wastes are currently incorporated in borosilicate glass matrices. The resulting glass must be perfectly homogeneous. The work discussed here is a study of actinide (thorium and plutonium) solubility in borosilicate glass, undertaken to assess the extent of actinide solubility in the glass and to understand the mechanisms controlling actinide solubilization. Glass specimens containing; actinide surrogates were used to prepare and optimize the fabrication of radioactive glass samples. These preliminary studies revealed that actinide Surrogates solubility in the glass was enhanced by controlling the processing temperature, the dissolution kinetic of the surrogate precursors, the glass composition and the oxidizing versus reducing conditions. The actinide solubility was investigated in the borosilicate glass. The evolution of thorium solubility in borosilicate glass was determined for temperatures ranging from 1200 deg C to 1400 deg C.Borosilicate glass specimens containing plutonium were fabricated. The experimental result showed that the plutonium solubility limit ranged from 1 to 2.5 wt% PuO2 at 1200 deg C. A structural approach based on the determination of the local structure around actinides and their surrogates by EXAFS spectroscopy was used to determine their structural role in the glass and the nature of their bonding with the vitreous network. This approach revealed a correlation between the length of these bonds and the solubility of the actinides and their surrogates. (author)

  14. Transmutation of minor actinide using thorium fueled BWR core

    One of the methods to conduct transmutation of minor actinide is the use of BWR with thorium fuel. Thorium fuel has a specific behaviour of producing a little secondary minor actinides. Transmutation of minor actinide is done by loading it in the BWR with thorium fuel through two methods, namely close recycle and accumulation recycle. The calculation of minor actinide composition produced, weigh of minor actinide transmuted, and percentage of reminder transmutation was carried SRAC. The calculations were done to equivalent cell modeling from one fuel rod of BWR. The results show that minor actinide transmutation is more effective using thorium fuel than uranium fuel, through both close recycle and accumulation recycle. Minor actinide transmutation weight show that the same value for those recycle for 5th recycle. And most of all minor actinide produced from 5 unit BWR uranium fuel can transmuted in the 6th of close recycle. And, the minimal value of excess reactivity of the core is 12,15 % Δk/k, that is possible value for core operation

  15. Separations chemistry for actinide elements: Recent developments and historical perspective

    With the end of the cold war, the principal mission in actinide separations has changed from production of plutonium to cleanup of the immense volume of moderately radioactive mixed wastes which resulted from fifty years of processing activities. In order to approach the cleanup task from a proper perspective, it is necessary to understand how the wastes were generated. Most of the key separations techniques central to actinide production were developed in the 40's and 50's for the identification and production of actinide elements. Total actinide recovery, lanthanide/actinide separations, and selective partitioning of actinides from inert constituents are currently of primary concern. To respond to the modern world of actinide separations, new techniques are being developed for separations ranging from analytical methods to detect ultra-trace concentrations (for bioassay and environmental monitoring) to large-scale waste treatment procedures. In this report, the history of actinide separations, both the basic science and production aspects, is examined and evaluated in terms of contemporary priorities

  16. Towards Synthesis and Usage of Actinide-Bearing REE Phosphate age Standards: A Progress Report

    Pyle, J. M.; Cherniak, D. J.

    2006-05-01

    Electron microprobe (EMP) dates result from a concentration-time unit conversion, so use of a concentration- based (rather than isotope-ratio based) fictive age standard is warranted. This observation has motivated our mineral synthesis program, aimed at producing actinide-doped REE phosphate EMP dating standards that meet the following criteria: 1) known concentrations of U, Th, and Pb; 2) homogeneous intragrain distribution of all components; 3) of suitable size, either as a single-crystal or polycrystalline sintered ceramic. Single-crystal synthesis of actinide-doped LaPO4 by flux-growth methods results in disproportionation of lanthanide and flux, alkali, and actinide components into phosphate and oxide phases, respectively, and flux- growth methods were abandoned. Actinide-doped La phosphate is successfully prepared by high-T annealing and hydrothermal processing of microcrystalline phosphate; both homogeneity and charge-balance of (Ca, Th, Pb)-bearing LaPO4 increase with increasing solvent acidity during cold-seal hydrothermal synthesis. A combination of pressing and high-T (1400° C) sintering transforms fine-grained (0.1-10 μm) run- products to ceramic pellets with 90-95% theoretical density. Our most recent runs focused on a target composition of La80(CaTh)17(CaU)2(PbTh)1PO4 processed with 6% 2M HCl at 820° C, 0.75 kbar for 1 week. The run products are 0.1-2 μm crystals identified by XRD as La-actinide phosphate solid solution. 2 μm grains (N=16) give a composition (mean±2 sd) of La79.77(1.26)(CaTh)17.87(1.00)(CaU)1.53(0.42)(PbTh)0.82(0.09)PO4. Th (8.07-9.13 wt. %) is homogeneous at the level of analytical precision, and the Pb concentration range (3500-4350 ppm) is restricted relative to untreated precipitate. Uranium concentration values are more variable (6500-10000 ppm). This run yields a fictive age of 702±4 Ma (mean±2 se), compared to the fictive age of 794 Ma for the target composition.

  17. Potentiometric Sensor for Real-Time Remote Surveillance of Actinides in Molten Salts

    Natalie J. Gese; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson

    2012-07-01

    A potentiometric sensor is being developed at the Idaho National Laboratory for real-time remote surveillance of actinides during electrorefining of spent nuclear fuel. During electrorefining, fuel in metallic form is oxidized at the anode while refined uranium metal is reduced at the cathode in a high temperature electrochemical cell containing LiCl-KCl-UCl3 electrolyte. Actinides present in the fuel chemically react with UCl3 and form stable metal chlorides that accumulate in the electrolyte. This sensor will be used for process control and safeguarding of activities in the electrorefiner by monitoring the concentrations of actinides in the electrolyte. The work presented focuses on developing a solid-state cation conducting ceramic sensor for detecting varying concentrations of trivalent actinide metal cations in eutectic LiCl-KCl molten salt. To understand the basic mechanisms for actinide sensor applications in molten salts, gadolinium was used as a surrogate for actinides. The ß?-Al2O3 was selected as the solid-state electrolyte for sensor fabrication based on cationic conductivity and other factors. In the present work Gd3+-ß?-Al2O3 was prepared by ion exchange reactions between trivalent Gd3+ from GdCl3 and K+-, Na+-, and Sr2+-ß?-Al2O3 precursors. Scanning electron microscopy (SEM) was used for characterization of Gd3+-ß?-Al2O3 samples. Microfocus X-ray Diffraction (µ-XRD) was used in conjunction with SEM energy dispersive X-ray spectroscopy (EDS) to identify phase content and elemental composition. The Gd3+-ß?-Al2O3 materials were tested for mechanical and chemical stability by exposing them to molten LiCl-KCl based salts. The effect of annealing on the exchanged material was studied to determine improvements in material integrity post ion exchange. The stability of the ß?-Al2O3 phase after annealing was verified by µ-XRD. Preliminary sensor tests with different assembly designs will also be presented.

  18. Actinide removal from nitric acid waste streams

    Actinide separations research at the Rocky Flats Plant (RFP) has found ways to significantly improve plutonium secondary recovery and americium removal from nitric acid waste streams generated by plutonium purification operations. Capacity and breakthrough studies show anion exchange with Dowex 1x4 (50 to 100 mesh) to be superior for secondary recovery of plutonium. Extraction chromatography with TOPO(tri-n-octyl-phosphine oxide) on XAD-4 removes the final traces of plutonium, including hydrolytic polymer. Partial neutralization and solid supported liquid membrane transfer removes americium for sorption on discardable inorganic ion exchangers, potentially allowing for non-TRU waste disposal

  19. Prediction of some fission properties of actinides

    The 2 Z-N correlations are indications for the deuteron-triton clusters structure to most of the nuclei. For N=Z nuclei this approach indicates deuteron clusters only. The space dependence Schroedinger equation for neutron and proton in the same shell for N=Z nuclei shows that part of the time these particles behave like single particles and part of the time as deuteron clusters. The 2 Z-N correlations are used to predict some fission properties of some actinides. (author). 13 refs., 6 Tabs

  20. Calculated Bulk Properties of the Actinide Metals

    Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.

    1978-01-01

    Self-consistent relativistic calculations of the electronic properties for seven actinides (Ac-Am) have been performed using the linear muffin-tin orbitals method within the atomic-sphere approximation. Exchange and correlation were included in the local spin-density scheme. The theory explains t...... the variation of the atomic volume and the bulk modulus through the 5f series in terms of an increasing 5f binding up to plutonium followed by a sudden localisation (through complete spin polarisation) in americium...

  1. The electrochemical properties of actinide amalgams

    Selection of the values of standard potentials of An actinides and their amalgams was made. On the basis of the data obtained energy characteristics of alloy formation processes in the systems An-Hg were calculated and analyzed. It is ascertained that the properties of f-element solutions in mercury are similar to those of alkali and alkaline-earth metal amalgams with the only difference, i.e. in case of active metals of group 3 the number of realized charge value of ionic frames in condensed phase increases

  2. Fission cross section measurements for minor actinides

    Fursov, B. [IPPE, Obninsk (Russian Federation)

    1997-03-01

    The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)

  3. Actinide behavior under final repository relevant conditions

    Experiments on the solubility behavior and the redox chemistry of actinides and long-living fission products under different geochemical boundary conditions, here on the Np(V) solubility in alkaline CaCl2 systems, provide basic information on processes that can occur in a nuclear final repository in case of water ingress. The thermodynamic constants derived from these experiments allow the geochemical modeling of these processes and a rough estimation of radionuclide solubility limits for different scenarios. Scientific research projects on this issue will reduce the uncertainties of long-term safety analyses for final repositories for high-level radioactive wastes significantly.

  4. Supercritical fluid extraction studies on actinides

    Uranyl nitrate and plutonium in its Pu (III) as well Pu (IV) form loaded onto a tissue paper was extracted completed from paper, glass, stainless steel as well as teflon matrices using modified SC-CO2. A further investigation on recovery of actinides independent of their drying period is expected to culminate into developing an universal procedure to handle Pu bearing waste for its recovery irrespective of its drying history and oxidation states. Such endeavors ultimately lead to the potential utility of the SFE technology for efficient nuclear waste management

  5. Recent progress in actinide borate chemistry

    Wang, S.; Alekseev, E .V.; Depmeier, W.; Albrecht-Schmitt, T.E.

    2011-01-01

    The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB(5)O(6)(OH)(6)][BO(OH)(2)]·2.5H(2)O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO(4)(-). Uranyl borates form noncentrosymmetric structures with extraordinarily rich topol...

  6. The electronic structure of the lanthanides and actinides, a comparison

    Full text: Optical spectra of the two f-element series (the lanthanides and actinides) are comparable in many respects. For the trivalent ions isolated in single crystals, both series exhibit rich, narrow line spectra. These data can be analysed in terms of a parametric model based on a free-ion Hamiltonian plus the addition of a crystal field Hamiltonian. For most systems the agreement between the calculated and experimental energy levels is quite good. In the actinide series there appears to be a correlation between the magnitude of the crystal field and the inadequacy of the fits. The early actinides exhibit multiple oxidation states for which there is no precedent in the lanthanide series. The parametric model mentioned earlier has been utilized for some tetravalent actinide systems with reasonably good results. A selective survey of results describing the similarities and differences of various lanthanide and actinide systems will be given

  7. Actinide coordination chemistry: towards the limits of the periodic table

    Actinide elements represent a distinct chemical family at the bottom of the periodic table. Among the major characteristics of this 14 element family is their high atomic numbers and their radioactivity. Actinide chemistry finds its roots in the history of the 20. century and plays a very important role in our contemporary world. Energetic as well as technical challenges are facing the development of nuclear energy. In this pedagogical introduction to actinide chemistry, the authors draw a comparison between the actinides family and the chemistry of two other families, lanthanides and transition metals. This article focuses on molecular and aqueous chemistry. It has been based on class notes aiming to present an overview of the chemical diversity of actinides, and its future challenges for modern science. (authors)

  8. Monitoring the bio-stimulation of hydrocarbon-contaminated soils by measurements of soil electrical properties, and CO2 content and its 13C/12C isotopic signature

    Noel, C.; Gourry, J.; Ignatiadis, I.; Colombano, S.; Dictor, M.; Guimbaud, C.; Chartier, M.; Dumestre, A.; Dehez, S.; Naudet, V.

    2013-12-01

    Hydrocarbon contaminated soils represent an environmental issue as it impacts on ecosystems and aquifers. Where significant subsurface heterogeneity exists, conventional intrusive investigations and groundwater sampling can be insufficient to obtain a robust monitoring of hydrocarbon contaminants, as the information they provide is restricted to vertical profiles at discrete locations, with no information between sampling points. In order to obtain wider information in space volume on subsurface modifications, complementary methods can be used like geophysics. Among geophysical methods, geoelectrical techniques such as electrical resistivity (ER) and induced polarization (IP) seem the more promising, especially to study the effects of biodegradation processes. Laboratory and field geoelectrical experiments to characterize soils contaminated by oil products have shown that mature hydrocarbon-contaminated soils are characterized by enhanced electrical conductivity although hydrocarbons are electrically resistive. This high bulk conductivity is due to bacterial impacts on geological media, resulting in changes in the chemical and physical properties and thus, to the geophysical properties of the ground. Moreover, microbial activity induced CO2 production and isotopic deviation of carbon. Indeed, produced CO2 will reflect the pollutant isotopic signature. Thus, the ratio δ13C(CO2) will come closer to δ13C(hydrocarbon). BIOPHY, project supported by the French National Research Agency (ANR), proposes to use electrical methods and gas analyses to develop an operational and non-destructive method for monitoring in situ biodegradation of hydrocarbons in order to optimize soil treatment. Demonstration field is located in the South of Paris (France), where liquid fuels (gasoline and diesel) leaked from some tanks in 1997. In order to stimulate biodegradation, a trench has been dug to supply oxygen to the water table and thus stimulate aerobic metabolic bioprocesses. ER and

  9. Isotopic geology

    Born from the application to geology of nuclear physics techniques, the isotopic geology has revolutionized the Earth's sciences. Beyond the dating of rocks, the tracer techniques have permitted to reconstruct the Earth's dynamics, to measure the temperatures of the past (giving birth to paleoclimatology) and to understand the history of chemical elements thanks to the analysis of meteorites. Today, all domains of Earth sciences appeal more or less to the methods of isotopic geology. In this book, the author explains the principles, methods and recent advances of this science: 1 - isotopes and radioactivity; 2 - principles of isotope dating; 3 - radio-chronological methods; 4 - cosmogenic isotope chronologies; 5 - uncertainties and radio-chronological results; 6 - geochemistry of radiogenic isotopes; 7 - geochemistry of stable isotopes; 8 - isotopic geology and dynamical analysis of reservoirs. (J.S.)

  10. Isotopic clusters

    Spectra of isotopically mixed clusters (dimers of SF6) are calculated as well as transition frequencies. The result leads to speculations about the suitability of the laser-cluster fragmentation process for isotope separation. (Auth.)

  11. A method for the determination of bacterial spore DNA content based on isotopic labelling, spore germination and diphenylamine assay; ploidy of spores of several Bacillus species

    A reliable method for measuring the spore DNA content, based on radioactive DNA labelling, spore germination in absence of DNA replication and diphenylamine assay, was developed. The accuracy of the method, within 10 - 15%, is adequate for determining the number of chromosomes per spore, provided that the genome size is known. B subtilis spores were shown to be invariably monogenomic, while those of larger bacilli Bacillus megaterium, Bacillus cereus and Bacillus thuringiensis, often, if not invariably, contain two genomes. Attempts to modify the spore DNA content of B subtilis by altering the richness of the sporulation medium, the sporulation conditions (liquid or solid medium), or by mutation, were apparently unsuccessful. An increase of spore size with medium richness, not accompanied by an increase in DNA content, was observed. The implication of the apparently species-specific spore ploidy and the influence of the sporulation conditions on spore size and shape are discussed

  12. Transmutation of minor actinides in a Candu thorium borner

    flattening as well as long term reactivity have been found by mixing thoria with 14% minor actinides in form of MAO2 in the central fuel bundle and decreasing radially MAO2 content at discrete levels down to 2% at the periphery. Furthermore, as alternative fuel, 5% UO2 has been added to the mixed fuel for the sake of a higher degree of nuclear safeguarding through denaturing the 233U component with 238U. The temporal variation of the criticality k∞ and the burn-up values of the reactor have been calculated for a period of 10 years, operated at full power. The criticality starts at time zero near to k∞ = ∼ 1.24 for both fuel compositions. A sharp decrease of the criticality has been observed during the first year as a consequence of rapid plutonium burnout in the actinide fuel. The criticality becomes quasi constant after the 2nd year after sufficient 233U is accumulated and remains close to k∞,end ∼1.06 over ∼ 10 years. Quasi-uniform power generation density has been realized in the fuel bundle throughout the reactor operation

  13. A systematic study of actinide production from the interactions of heavy ions with 248Cm

    Production cross sections for heavy actinides produced from the interactions of 12C, 31P, 40Ar, and 44Ca ions with 248Cm were measured at energies ranging from 0.98 to 1.35 X Coulomb barrier. The recoiling reaction products were collected in copper or gold catcher foils located near the 248Cm target. Separate fractions of Bk, Cf, Es, Fm, and Md were obtained from a radiochemical separation procedure. For the 12C system, a He/KCl jet was used to transport the recoiling No activities of interest to a rotating wheel system. The isotopic distributions of the actinide products were found to be essentially symmetric about the maximum with full-widths-at-half-maximum of approximately 2.5 mass units. Isotopic distributions of the 12C, 31P, 40Ar, and 44Ca systems were found to be very similar to the 40,48Ca systems studied previously. The maxima of the isotopic distributions generally occurred for those reaction channels which involved the exchange of the fewest number of nucleons between the target and projectile for which the calculated excitation energy was a positive quantity. Additionally, the maxima of the excitation functions occurred at those projectile energies which were consistent with the calculated reaction barriers based upon a binary reaction mechanism. The experimental data from the four systems investigated were compared to several models of heavy ion interactions including a damped reaction mechanism, compound nucleus formation and subsequent particle evaporation, and classical partial wave calculations for binary systems

  14. Recharge Area on the Slopes of Volcano Based on Geological Setting, Content of Deuterium and Oxygen Isotopes of Groundwater Chemistry: Case Study on the Slopes of Salak Mountain, West Java

    Hendarmawan

    2011-09-01

    Full Text Available Indonesian is huge areas that have the highest precipitation in the world, therefore water deficit of groundwater is often happened at anywhere. This study was related to determination of recharge area with approached by combining geological setting, stable isotopes and chemical content of groundwater. Case study was carried out at surrounding the Cicurug area, Sukabumi Prefecture, West Java Province. The area is the slopes of Salak Mountain that have elevation of 400 until 1,200 m mean sea level (msl. While, much groundwater supplies industry activities on elevation 450-500 m msl. Based on data and result analysis of the studies, the recharge areas was not around peak of mountain or near, but water infiltrated on elevation of 700-800 m msl for groundwater exploited by industries. Therefore, the accurate determination of recharge area becomes a key for the groundwater sustainability.

  15. Decorporation of inhaled actinides by chelation therapy

    This article describes recent work in NRPB laboratories that has identified some of the factors influencing the behaviour of plutonium, americium and curium compounds in the body after inhalation, together with a number of experimental approaches that are being developed to optimise their treatment with DTPA. It is concluded that the most effective treatment has yet to be developed, but progress must depend on a better understanding of the factors governing the transport of actinides in the body. It cannot be assumed that because the inhaled material is readily translocated to blood, that treatment regimens with Ca-DTPA based solely on previous understanding of the metabolic fate of soluble actinide complexes will be successful. In fact, depending on the nature of the material involved in the accident, inhalation alone or combined with prolonged infusion of DTPA may be more effective than the periodic intravenous injections of the chelating agent alone. For poorly transportable materials such as insoluble plutonium-239 dioxide, chelation treatment remains essentially ineffective. (U.K.)

  16. Actinide Solubility and Speciation in the WIPP

    Reed, Donald T. [Los Alamos National Laboratory

    2015-11-02

    The presentation begins with the role and need for nuclear repositories (overall concept, international updates (Sweden, Finland, France, China), US approach and current status), then moves on to the WIPP TRU repository concept (design, current status--safety incidents of February 5 and 14, 2014, path forward), and finally considers the WIPP safety case: dissolved actinide concentrations (overall approach, oxidation state distribution and redox control, solubility of actinides, colloidal contribution and microbial effects). The following conclusions are set forth: (1) International programs are moving forward, but at a very slow and somewhat sporadic pace. (2) In the United States, the Salt repository concept, from the perspective of the long-term safety case, remains a viable option for nuclear waste management despite the current operational issues/concerns. (3) Current model/PA prediction (WIPP example) are built on redundant conservatisms. These conservatisms are being addressed in the ongoing and future research to fill existing data gaps--redox control of plutonium by Fe(0, II), thorium (analog) solubility studies in simulated brine, contribution of intrinsic and biocolloids to the mobile concentration, and clarification of microbial ecology and effects.

  17. Electronic structure of the actinide dioxides

    The electronic properties of the fluorite structured actinide dioxides have been investigated using the linear muffin tin orbital method in the atomic sphere approximation. CaF2 with the same structure was also studied because of the relative simplicity of its electronic structure and the greater amount of experimental data available. Band structures were calculated both non self consistently and self consistently. In the non self consistent calculations the effect of changing the approximation to the exchange-correlation potential and the starting atomic configurations was examined. Using the concepts of canonical bands the effects of hybridization were investigated. In particular the 5f electrons included in the band picture were found to mix more strongly into the valence band than indicated by experiment. On this basis the 5f electrons were not included in self consistent calculations which in the density functional formalism are capable of yielding ground state properties. Because of the non participation of the f electrons in the bonding UO2 only was considered as representative of the actinide dioxides. For comparison CaF2 was also examined. Using Pettifor's pressure formula to determine the equilibrium condition the lattice constants were calculated to be 0.5% and 5% respectively below the experimental values. (author)

  18. Evaluation of average neutron resonance parameters of actinides with the account of experimental resolution and discrimination threshold. Final report for the period 15 December 1996 - 14 December 1997

    New evaluation of average resonance parameters for 32 isotopes of the actinide region (229Th-252Cf) was completed. Obtained values of average level spacings produce a smooth systematics of the main level density parameter. The results were included into the Starter File of the Reference Input Parameter Library (segment Average Neutron Resonances) and officially released on 15 May 1998. The numerical results are available from the Internet (http://iaeand.iaea.or.at/ripl) and on CD-ROM. (author)

  19. A methodology for evaluating the performance of software, using γ spectrometry, for determining the isotopic composition of plutonium

    This paper presents the progress of an ongoing study regarding the performances of software used for determining the isotopic composition of plutonium and uranium, by means of γ spectrometry, in the presence of 'disturbing' radioactive emitters and of various matrices. The 'disturbing' radio-emitters are some minor actinides (Am242, Am243, Np237, Cm243 etc.), fission products (Cs137, Sb125, Eu154 etc.) and/or activation products (Co60 etc.). All these radionuclides can be found in waste from the nuclear industry. Matrices can also vary (metal, vinyl...) and have a disturbing impact on the results given by the software for determining the isotopic composition (IC). The original aim of the study was to determine the field of applicability of each IC determination software tool when considering various types of package, radiological contents, measurement conditions and configuration and equipment. The proposed method involved the 3 following steps. First step: the acquisition of elementary mono-isotopic or mono-elemental spectra on mock-up packages with standard sources in well defined measurement conditions in order to establish a common database. Second step: the computation of virtual spectra by summing these 'elementary' spectra on each channel (in the same conditions). Third step: testing these virtual spectra with the various software tools

  20. Recycled oceanic crust and marine sediment in the source of alkali basalts in Shandong, eastern China: Evidence from magma water content and oxygen isotopes

    Liu, Jia; Xia, Qun-Ke; Deloule, Etienne; Chen, Huan; Feng, Min

    2015-12-01

    The magma water contents and cpx δ18O values in alkali basalts from the Fuyanyshan (FYS) volcano in Shandong, eastern China, were investigated by an inverse calculation based on the water content of clinopyroxene (cpx) phenocrysts, the ivAlcpx-dependent water partitioning coefficient Dwatercpx>/melt, and secondary ion mass spectrometer, respectively. The calculated water content (H2O wt.) of magma ranges from 0.58% to 3.89%. It positively correlates with heavy rare earth element concentrations and bulk rock 87Sr/86Sr ratios, and it negatively correlates with Nb/U ratios. However, it is not correlated with bulk Mg# (Mg# = 100 × Mg / (Mg + Fe)) and (La/Yb)n (n represents primitive mantle normalization). Combined with the rather homogenous distribution of water content within cpx grains, these correlations indicate that the water variations among different samples represent the original magma signature, rather than results of a shallow process, such as degassing and diffusion. The δ18O of cpx phenocrysts varies from 3.6‰ to 6.3‰ (±0.5‰, 2SD), which may be best explained by the involvement of components from the lower and upper oceanic crust with marine sediments within the mantle source. The H2O/Ce ratios of the calculated melts range from 113 to 696 and form a positive trend with bulk rock 87Sr/86Sr, which cannot be explained by the recycled Sulu eclogite or by the metasomatized lithospheric mantle. Our modeling calculation shows that the decoupling of ɛHf and ɛNd could be caused by the involvement of marine sediments. Combing the high Ba/Th ratios, positive Sr spikes, and low Ce/Pb ratios for the Fuyanshan basalts, we suggest that the hydrous nature of the FYS basalts was derived from the hydrous mantle transition zone with ancient sediments.

  1. Separation of actinides from spent nuclear fuel: A review.

    Veliscek-Carolan, Jessica

    2016-11-15

    This review summarises the methods currently available to extract radioactive actinide elements from solutions of spent nuclear fuel. This separation of actinides reduces the hazards associated with spent nuclear fuel, such as its radiotoxicity, volume and the amount of time required for its' radioactivity to return to naturally occurring levels. Separation of actinides from environmental water systems is also briefly discussed. The actinide elements typically found in spent nuclear fuel include uranium, plutonium and the minor actinides (americium, neptunium and curium). Separation methods for uranium and plutonium are reasonably well established. On the other hand separation of the minor actinides from lanthanide fission products also present in spent nuclear fuel is an ongoing challenge and an area of active research. Several separation methods for selective removal of these actinides from spent nuclear fuel will be described. These separation methods include solvent extraction, which is the most commonly used method for radiochemical separations, as well as the less developed but promising use of adsorption and ion-exchange materials. PMID:27427893

  2. Gas core reactors for actinide transmutation. [uranium hexafluoride

    Clement, J. D.; Rust, J. H.; Wan, P. T.; Chow, S.

    1979-01-01

    The preliminary design of a uranium hexafluoride actinide transmutation reactor to convert long-lived actinide wastes to shorter-lived fission product wastes was analyzed. It is shown that externally moderated gas core reactors are ideal radiators. They provide an abundant supply of thermal neutrons and are insensitive to composition changes in the blanket. For the present reactor, an initial load of 6 metric tons of actinides is loaded. This is equivalent to the quantity produced by 300 LWR-years of operation. At the beginning, the core produces 2000 MWt while the blanket generates only 239 MWt. After four years of irradiation, the actinide mass is reduced to 3.9 metric tonnes. During this time, the blanket is becoming more fissile and its power rapidly approaches 1600 MWt. At the end of four years, continuous refueling of actinides is carried out and the actinide mass is held constant. Equilibrium is essentially achieved at the end of eight years. At equilibrium, the core is producing 1400 MWt and the blanket 1600 MWt. At this power level, the actinide destruction rate is equal to the production rate from 32 LWRs.

  3. Evaluation of possible physical-chemical processes that might lead to separations of actinides in ORNL waste tanks

    Del Cul, G.D.; Toth, L.M.; Bond, W.D.; Dai, S.

    1997-09-01

    The concern that there might be some physical-chemical process which would lead to a separation of the poisoning actinides ({sup 232}Th, {sup 238}U) from the fissionable ones ({sup 239}Pu, {sup 235}U) in waste storage tanks at Oak Ridge National Laboratory has led to a paper study of potential separations processes involving these elements. At the relatively high pH values (>8), the actinides are normally present as precipitated hydroxides. Mechanisms that might then selectively dissolve and reprecipitate the actinides through thermal processes or additions of reagents were addressed. Although redox reactions, pH changes, and complexation reactions were all considered, only the last type was regarded as having any significant probability. Furthermore, only carbonate accumulation, through continual unmonitored air sparging of the tank contents, could credibly account for gross transport and separation of the actinide components. From the large amount of equilibrium data in the literature, concentration differences in Th, U, and Pu due to carbonate complexation as a function of pH have been presented to demonstrate this phenomenon. While the carbonate effect does represent a potential separations process, control of long-term air sparging and solution pH, accompanied by routine determinations of soluble carbonate concentration, should ensure that this separations process does not occur.

  4. Evaluation of possible physical-chemical processes that might lead to separations of actinides in ORNL waste tanks

    The concern that there might be some physical-chemical process which would lead to a separation of the poisoning actinides (232Th, 238U) from the fissionable ones (239Pu, 235U) in waste storage tanks at Oak Ridge National Laboratory has led to a paper study of potential separations processes involving these elements. At the relatively high pH values (>8), the actinides are normally present as precipitated hydroxides. Mechanisms that might then selectively dissolve and reprecipitate the actinides through thermal processes or additions of reagents were addressed. Although redox reactions, pH changes, and complexation reactions were all considered, only the last type was regarded as having any significant probability. Furthermore, only carbonate accumulation, through continual unmonitored air sparging of the tank contents, could credibly account for gross transport and separation of the actinide components. From the large amount of equilibrium data in the literature, concentration differences in Th, U, and Pu due to carbonate complexation as a function of pH have been presented to demonstrate this phenomenon. While the carbonate effect does represent a potential separations process, control of long-term air sparging and solution pH, accompanied by routine determinations of soluble carbonate concentration, should ensure that this separations process does not occur

  5. Principle and Uncertainty Quantification of an Experiment Designed to Infer Actinide Neutron Capture Cross-Sections

    G. Youinou; G. Palmiotti; M. Salvatorre; G. Imel; R. Pardo; F. Kondev; M. Paul

    2010-01-01

    An integral reactor physics experiment devoted to infer higher actinide (Am, Cm, Bk, Cf) neutron cross sections will take place in the US. This report presents the principle of the planned experiment as well as a first exercise aiming at quantifying the uncertainties related to the inferred quantities. It has been funded in part by the DOE Office of Science in the framework of the Recovery Act and has been given the name MANTRA for Measurement of Actinides Neutron TRAnsmutation. The principle is to irradiate different pure actinide samples in a test reactor like INL’s Advanced Test Reactor, and, after a given time, determine the amount of the different transmutation products. The precise characterization of the nuclide densities before and after neutron irradiation allows the energy integrated neutron cross-sections to be inferred since the relation between the two are the well-known neutron-induced transmutation equations. This approach has been used in the past and the principal novelty of this experiment is that the atom densities of the different transmutation products will be determined with the Accelerator Mass Spectroscopy (AMS) facility located at ANL. While AMS facilities traditionally have been limited to the assay of low-to-medium atomic mass materials, i.e., A < 100, there has been recent progress in extending AMS to heavier isotopes – even to A > 200. The detection limit of AMS being orders of magnitude lower than that of standard mass spectroscopy techniques, more transmutation products could be measured and, potentially, more cross-sections could be inferred from the irradiation of a single sample. Furthermore, measurements will be carried out at the INL using more standard methods in order to have another set of totally uncorrelated information.

  6. New Developments in Actinides Burning with Symbiotic LWR-HTR-GCFR Fuel Cycles

    The long-term radiotoxicity of the final waste is currently the main drawback of nuclear power production. Particularly, isotopes of Neptunium and Plutonium along with some long-lived fission products are dangerous for more than 100000 years. 96% of spent Light Water Reactor (LWR) fuel consists of actinides, hence it is able to produce a lot of energy by fission if recycled. Goals of Generation IV Initiative are reduction of long-term radiotoxicity of waste to be stored in geological repositories, a better exploitation of nuclear fuel resources and proliferation resistance. Actually, all these issues are intrinsically connected with each other. It is quite clear that these goals can be achieved only by combining different concepts of Gen. IV nuclear cores in a 'symbiotic' way. Light-Water Reactor - (Very) High Temperature Reactor ((V)HTR) - Fast Reactor (FR) symbiotic cycles have good capabilities from the viewpoints mentioned above. Particularly, HTR fuelled by Plutonium oxide is able to reach an ultra-high burn-up and to burn Neptunium and Plutonium effectively. In contrast, not negligible amounts of Americium and Curium build up in this core, although the total mass of Heavy Metals (HM) is reduced. Americium and Curium are characterised by an high radiological hazard as well. Nevertheless, at least Plutonium from HTR (rich in non-fissile nuclides) and, if appropriate, Americium can be used as fuel for Fast Reactors. If necessary, dedicated assemblies for Minor Actinides (MA) burning can be inserted in Fast Reactors cores. This presentation focuses on combining HTR and Gas Cooled Fast Reactor (GCFR) concepts, fuelled by spent LWR fuel and depleted uranium if need be, to obtain a net reduction of total mass and radiotoxicity of final waste. The intrinsic proliferation resistance of this cycle is highlighted as well. Additionally, some hints about possible Curium management strategies are supplied. Besides, a preliminary assessment of different chemical forms of

  7. New Developments in Actinides Burning with Symbiotic LWR-HTR-GCFR Fuel Cycles

    Bomboni, Eleonora [Department of Mechanical, Nuclear and Production Engineering (DIMNP), Via Diotisalvi 2 - 56100 Pisa (Italy)

    2008-07-01

    The long-term radiotoxicity of the final waste is currently the main drawback of nuclear power production. Particularly, isotopes of Neptunium and Plutonium along with some long-lived fission products are dangerous for more than 100000 years. 96% of spent Light Water Reactor (LWR) fuel consists of actinides, hence it is able to produce a lot of energy by fission if recycled. Goals of Generation IV Initiative are reduction of long-term radiotoxicity of waste to be stored in geological repositories, a better exploitation of nuclear fuel resources and proliferation resistance. Actually, all these issues are intrinsically connected with each other. It is quite clear that these goals can be achieved only by combining different concepts of Gen. IV nuclear cores in a 'symbiotic' way. Light-Water Reactor - (Very) High Temperature Reactor ((V)HTR) - Fast Reactor (FR) symbiotic cycles have good capabilities from the viewpoints mentioned above. Particularly, HTR fuelled by Plutonium oxide is able to reach an ultra-high burn-up and to burn Neptunium and Plutonium effectively. In contrast, not negligible amounts of Americium and Curium build up in this core, although the total mass of Heavy Metals (HM) is reduced. Americium and Curium are characterised by an high radiological hazard as well. Nevertheless, at least Plutonium from HTR (rich in non-fissile nuclides) and, if appropriate, Americium can be used as fuel for Fast Reactors. If necessary, dedicated assemblies for Minor Actinides (MA) burning can be inserted in Fast Reactors cores. This presentation focuses on combining HTR and Gas Cooled Fast Reactor (GCFR) concepts, fuelled by spent LWR fuel and depleted uranium if need be, to obtain a net reduction of total mass and radiotoxicity of final waste. The intrinsic proliferation resistance of this cycle is highlighted as well. Additionally, some hints about possible Curium management strategies are supplied. Besides, a preliminary assessment of different chemical

  8. Actinide separation chemistry in nuclear waste streams and materials

    The separation of actinide elements from various waste materials, produced either in nuclear fuel cycles or in past nuclear weapons production, represents a significant issue facing developed countries. Improvements in the efficiencies of the separation processes can be expected to occur as a result of better knowledge of the elements in these complex matrices. The Nuclear Science Committee of the OECD/NEA has established a task force of experts in actinide separation chemistry to review current and developing separation techniques and chemical processes. The report consist of eight chapters. In Chapter 1 the importance of actinide separation chemistry in the fields of waste management and its background are summarized.In Chapter 2 the types of waste streams are classified according to their relative importance, by physical form and by source of actinides. The basic data of actinide chemical thermodynamics, such as oxidation states, hydrolysis, complexation, sorption, Gibbs energies of formation, and volatility, were collected and are presented in Chapter 3. Actinide analyses related to separation processes are also mentioned in this chapter. The state of the art of actinide separation chemistry is classified in three groups, including hydrometallurgy, pyrochemical process and process based on fields, and is described in Chapter 4 along with the relationship of kinetics to separations. In Chapter 5 basic chemistry research needs and the inherent limitation on separation processes are discussed. Prioritization of research and development is discussed in Chapter 6 in the context of several attributes of waste management problems. These attributes include: mass or volume of waste; concentration of the actinide in the waste; expected difficulty of treating the wastes; short-term hazard of the waste; long-term hazard of the waste; projected cost of treatment; amount of secondary waste. Based on the priority, recommendations were made for the direction of future research

  9. Thermodynamics proposes, kinetics decides, speciation dares: speciation of actinides in biological media

    After having recalled the content and purpose of his research thesis, the author proposes a detailed overview of the research works he performed thereafter in the field of the speciation of actinides at the level of the organism entry gates and in target tissues. These works therefore concern four important areas of research in radioprotection: bio-kinetic, toxicology, decorporation, and dosimetry studies. The author outlines how speciation studies can be useful for these different areas, and to better understand and describe, and therefore foresee, the biokinetics and toxicity of radionuclides

  10. Minor actinides impact on basic safety parameters of medium-sized sodium-cooled fast reactor

    Darnowski Piotr; Uzunow Nikolaj

    2015-01-01

    An analysis of the influence of addition of minor actinides (MA) to the fast reactor fuel on the most important safety characteristics was performed. A special emphasis was given to the total control rods worth in order to describe qualitatively and quantitatively its change with MA content. All computations were performed with a homogeneous assembly model of modified BN-600 sodium-cooled fast reactor core with 0, 3 and 6% of MA. A model was prepared for the Monte Carlo neutron transport code...

  11. Plutonium, americium and other actinides on Belarus territory: source, levels, risks

    For Belarus it was showed that in result of falling during nuclear trials happened contamination of upper soil layer by transuranium elements with medium level of contamination for 239,240Pu 53±17 Bq/m2. After Chernobyl accident this characteristic equal 1.1· Bq/m2 on the south of Belarus. In result accident it was revealed 17 actinides. For Chernobyl falling was determined big contents of 241Pu that will lead to maximum value of 241Am in 2059, which will be more in 2,5 times than 239,240Pu

  12. Status report on actinide and fission product transmutation studies

    The management of radioactive waste is one of the key issues in today's political and public discussions on nuclear energy. One of the fields that looks into the future possibilities of nuclear technology is the neutronic transmutation of actinides and of some most important fission products. Studies on transmutation of actinides are carried out in various countries and at an international level. This status report which gives an up-to-date general overview of current and planned research on transmutation of actinides and fission products in non-OECD countries, has been prepared by a Technical Committee meeting organized by the IAEA in September 1995. 168 refs, 16 figs, 34 tabs

  13. The speciation of actinide ions in concentrated salt solutions

    Many separations of actinide ions involve concentrated solutions. There is additional interest in actinide behavior in brine solutions in the WIPP salt repository. Unfortunately, little understanding exists on the speciation of actinides in concentrated solutions. The author has studied the extraction distribution of Am(III) as a function of concentration of NX salts (N-, Li+, Na+, K+, NH4+ and X = ClO4-, Cl-, NO3-). Analyses of the distribution curves are discussed in terms of hydration, complexation, etc. effects on the Am(III). The variation of the calculated stability constants with ionic strength is compared with the expected variation using Specific-Ion Interaction Theory (SIT)

  14. Review of actinide nitride properties with focus on safety aspects

    This report provides a review of the potential advantages of using actinide nitrides as fuels and/or targets for nuclear waste transmutation. Then a summary of available properties of actinide nitrides is given. Results from irradiation experiments are reviewed and safety relevant aspects of nitride fuels are discussed, including design basis accidents (transients) and severe (core disruptive) accidents. Anyway, as rather few safety studies are currently available and as many basic physical data are still missing for some actinide nitrides, complementary studies are proposed. (author)

  15. Actinide interactions at microbial interfaces: an interdisciplinary challenge

    An overview on the current state of knowledge of microbial actinide interaction processes is presented. Several detailed examples of the interaction of aerobic soil bacteria (Pseudomonas, Bacillus and Deinococcus strains) with uranium and plutonium are discussed. Details of the nature of the bacterial functional groups involved in the interfacial actinide interaction process are reported. Based on time-resolved laser-induced fluorescence spectroscopy (TRLFS) and synchrotron X-ray absorption spectroscopy (XANES and EXAFS) studies, molecular-level mechanistic details of the different interaction processes are discussed. Areas of this emerging field in actinide research are outlined where additional information and integrated interdisciplinary research is required

  16. Review of actinide nitride properties with focus on safety aspects

    Albiol, Thierry [CEA Cadarache, St Paul Lez Durance Cedex (France); Arai, Yasuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-12-01

    This report provides a review of the potential advantages of using actinide nitrides as fuels and/or targets for nuclear waste transmutation. Then a summary of available properties of actinide nitrides is given. Results from irradiation experiments are reviewed and safety relevant aspects of nitride fuels are discussed, including design basis accidents (transients) and severe (core disruptive) accidents. Anyway, as rather few safety studies are currently available and as many basic physical data are still missing for some actinide nitrides, complementary studies are proposed. (author)

  17. Separating the Minor Actinides Through Advances in Selective Coordination Chemistry

    Lumetta, Gregg J.; Braley, Jenifer C.; Sinkov, Sergey I.; Carter, Jennifer C.

    2012-08-22

    This report describes work conducted at the Pacific Northwest National Laboratory (PNNL) in Fiscal Year (FY) 2012 under the auspices of the Sigma Team for Minor Actinide Separation, funded by the U.S. Department of Energy Office of Nuclear Energy. Researchers at PNNL and Argonne National Laboratory (ANL) are investigating a simplified solvent extraction system for providing a single-step process to separate the minor actinide elements from acidic high-level liquid waste (HLW), including separating the minor actinides from the lanthanide fission products.

  18. Electronic structure and ionicity of actinide oxides from first principles

    Petit, Leon; Svane, Axel; Szotek, Z.;

    2010-01-01

    The ground-state electronic structures of the actinide oxides AO, A2O3, and AO2 (A=U, Np, Pu, Am, Cm, Bk, and Cf) are determined from first-principles calculations, using the self-interaction corrected local spin-density approximation. Emphasis is put on the degree of f-electron localization, which...... actinide dioxides is discussed, and it is found that the dioxide is the most stable oxide for the actinides from Np onward. Our study reveals a strong link between preferred oxidation number and degree of localization which is confirmed by comparing to the ground-state configurations of the corresponding...

  19. Evaluation of Homogeneous Options: Effects of Minor Actinide Exclusion from Single and Double Tier Recycle in Sodium Fast Reactors

    R. M. Ferrer; S. Bays; M. Pope

    2008-03-01

    The Systems Analysis Campaign under the Global Nuclear Energy Partnership (GNEP) has requested the fuel cycle analysis group at the Idaho National Laboratory (INL) to analyze and provide isotopic data for four scenarios in which different strategies for Minor Actinides (MA) management are investigated. A 1000 MWth commercial-scale Sodium Fast Reactor (SFR) design was selected as the baseline in this scenario study. Two transuranic (TRU) conversion ratios, defined as the ratio of the amount of TRU produced over the TRU destroyed in the reactor core, along with different fuel-types were investigated.

  20. Cryogenic gamma detectors enable direct detection of 236U and minor actinides for non-destructive assay

    We demonstrate the utility of a superconducting transition edge sensor (TES) γ-ray detector with high energy resolution and low Compton background for nondestructive assay (NDA) of a uranium sample from reprocessed nuclear fuel. We show that TES γ-detectors can separate low-energy actinide γ-emissions from the background and nearby lines, even from minor isotopes whose signals are often obscured in NDA with conventional Ge detectors. Superconducting γ-detectors may therefore bridge the gap between high-accuracy destructive assay (DA) and easier-to-use NDA. (author)

  1. Isotopic signatures: An important tool in today`s world

    Rokop, D.J.; Efurd, D.W.; Benjamin, T.M.; Cappis, J.H.; Chamberlin, J.W.; Poths, H.; Roensch, F.R.

    1995-12-01

    High-sensitivity/high-accuracy actinide measurement techniques developed to support weapons diagnostic capabilities at the Los Alamos National Laboratory are now being used for environmental monitoring. The measurement techniques used are Thermal Ionization Mass Spectrometry (TIMS), Alpha Spectrometry(AS), and High Resolution Gamma Spectrometry(HRGS). These techniques are used to address a wide variety of actinide inventory issues: Environmental surveillance, site characterizations, food chain member determination, sedimentary records of activities, and treaty compliance concerns. As little as 10 femtograms of plutonium can be detected in samples and isotopic signatures determined on samples containing sub-100 femtogram amounts. Uranium, present in all environmental samples, can generally yield isotopic signatures of anthropogenic origin when present at the 40 picogam/gram level. Solid samples (soils, sediments, fauna, and tissue) can range from a few particles to several kilograms in size. Water samples can range from a few milliliters to as much as 200 liters.

  2. Recovery of trivalent lanthanides and actinides from water deficient nitrate media by TBP-extraction

    The equilibrium distributions of trivalent lanthanides, Am and Cm were experimentally studied in the bi-phase extraction system of TBP-dodecane and molten Ca(NO3)2xxH2O (hydrate melt) having different water content. The systematics of the distribution ratios along lanthanides series was analyzed. It was found that the distribution ratios of lanthanides and actinides ar quite high and show logarithmically linear increase on log[TBP] in the low TBP concentration ( 0.1 mol/1). The influence of the water content in the hydrate melt was studied and it was shown that even a small increase of water content significantly lowers the extraction of trivalent elements. These characteristics of the TBP extraction using hydrate melt of Ca(NO3)2 were compared with TBP extraction system using concentrated nitric acid as inorganic phase. Based on the experimental results, feasibility and condition of the extraction recovery of trivalent lanthanides and actinides by the TBP from hydrate melt of Ca(NO3)2 were discussed. (author)

  3. Climate and isotopic tracers

    The applications of natural radioactivity and isotopic measurements in the sciences concerning Earth and its atmosphere, are numerous: carbon 14 dating with the Tandetron apparatus at the Cea, measurement of oxygen 18 in coral or sediment limestone for the determination of ocean temperature and salinity, carbon 14 dating of corals for the determination of sea level variations, deuterium content in polar ice-cap leads to temperature variations determination; isotopic measurements also enable the determination of present climate features such as global warming, oceanic general circulation

  4. Role of actinide behavior in waste management

    For purposes of assessing the safety of repositories of radioactive wastes placed in geologic isolation, actinide behavior in the environment has been interpreted in terms of five steps of prediction: analysis of repository stability; geosphere transport; the geosphere-biosphere interface; biosphere transport; and biosphere consequences. Each step in the analysis requires models of nuclide behavior and data on the physical and chemical properties of the radioactivity. The scope of information required in order to make reliable safety assessments has been outlined. All steps in the assessment process are coupled; reliable models and data are therefore needed for each step. The prediction phase of safety assessment is also coupled to activities concerned with waste treatment, selection of the final form of the waste, and selection of repository sites and designs. Results of the predictions can impact these activities

  5. Solidification of simulated actinides by natural zircon

    YANG Jian-Wen; LUO Shang-Geng

    2004-01-01

    Natural zircon was used as precursor material to produce a zircon waste form bearing 20wt% simulated actinides (Nd2O3 and UO2) through a solid state reaction by a typical synroc fabrication process. The fabricated zircon waste form has relatively good physical properties (density 5.09g/cm3, open porosity 4.0%, Vickers hardness 715kg/mm2). The XRD, SEM/EDS and TEM/EDS analyses indicate that there are zircon phases containing waste elements formed through the reaction. The chemical durability and radiation stability are determined by the MCC-1method and heavy ion irradiation; the results show that the zircon waste form is highly leach resistance and relatively stable under irradiation (amorphous dose 0.7dpa). From this study, the method of using a natural mineral to solidify radioactive waste has proven to be feasible.

  6. Actinide elements in aquatic and terrestrial environments

    Progress is reported in terrestrial ecology studies with regard to plutonium in biota from the White Oak Creek forest; comparative distribution of plutonium in two forest ecosystems; an ecosystem model of plutonium dynamics; actinide element metabolism in cotton rats; and crayfish studies. Progress is reported in aquatic studies with regard to transuranics in surface waters, frogs, benthic algae, and invertebrates from pond 3513; and radioecology of transuranic elements in cotton rats bordering waste pond 3513. Progress is also reported in stability of trivalent plutonium in White Oak Lake water; chemistry of plutonium, americium, curium, and uranium in pond water; uranium, thorium, and plutonium in small mammals; and effect of soil pretreatment on the distribution of plutonium

  7. In-situ monitoring of actinides and rare earth elements by electrothermal hollow cathode discharge spectrometry

    This report describes an Electrothermal Hollow Cathode Discharge Spectrometry (ET-HCDS) source being constructed for the analytical determination of actinides and rare earth elements. This work was initiated with the support of the Office of Safeguards and Security; the Buried Waste Integrated Demonstration began funding work in this area in mid-FY1992 and the work is continuing into FY1993 with funds from both sources. Special features of this instrument should permit it to be used for the determination of individual isotopic species, which is important for safeguard's materials control and accountancy. ET-HCDS can be achieved using compact instrumentation suitable for use in field laboratories. The technique is capable of determining a suite of environmentally-important species, such as the actinides and the heavy metals, in a variety of physical forms (e.g., in solution, as found on air particulates, or in soils). ET-HCDS should be capable of very sensitive analyses and should require very small samples (e.g., microgram). Since ET-HCDS is possible in an air atmosphere (at reduced pressures), it may be useful for the real-time determination of hazardous materials, both radioactive and non radioactive, contained in dusts released during waste retrieval operations; ET-HCDS should also be useful for the rapid and sensitive analysis of metals in soils

  8. Measurement of fast neutron induced fission cross section of minor-actinide

    In fuel cycles with recycled actinide, core characteristics are largely influenced by minor actinide (MA: Np, Am, Cm). Accurate nuclear data of MA such as fission cross section are required to estimate the effect of MA with high accuracy. In this study, fast neutron induced fission cross section of MA is measured using Dynamitron Accelerator in Tohoku University. The experimental method and the samples, which were developed or introduced during the last year, were improved in this fiscal year: (1) Development of a sealed fission chamber, (2) Intensification of Li neutron target, (3) Improvement of time-resolution of Time-of-Flight (TOF) electronic circuit, (4) Introduction of Np237 samples with large sample mass and (5) Introduction of a U235 sample with high purity. Using these improved tools and samples, the fission cross section ratio of Np237 relative to U235 was measured between 5 to 100 keV, and the fission cross section of Np237 was deduced. On the other hand, samples of Am241 and Am243 were obtained from Japan Atomic Energy Research Institute (JAERI) after investigating fission cross section of two americium isotopes (Am241 and Am 243) which are important for core physics calculation of fast reactors. (author)

  9. Study of actinides fission induced by multi-nucleon transfer reactions in inverse kinematics

    The study of actinide fission encounters two major issues. On one hand, measurements of the fission fragment distributions and the fission probabilities allow a better understanding of the fission process itself and the discrimination among the models of nuclear structure and dynamics. On the other hand, new measurements are required to improve nuclear data bases, which are a key component for the design of new generation reactors and radio-toxic waste incinerators. This thesis is in line with different French and American experimental projects using the surrogate method, i.e. transfer reactions leading to the same compound nuclei as in neutron irradiation, allowing the study of fission of actinides which are inaccessible by conventional techniques, whereas they are important for applications. The experiment is based on multi-nucleon transfer reactions between a 238U beam and a 12C target, using the inverse kinematics technique to measure, for each transfer channel, the complete isotopic distributions of the fission fragments with the VAMOS spectrometer. The work presented in this dissertation is focused on the identification of the transfer channels and their properties, as their angular distributions and the distributions of the associated excitation energy, using the SPIDER telescope to identify the target recoil nuclei. This work of an exploratory nature aims to generalize the surrogate method to heavy transfers and to measure, for the first time, the fission probabilities in inverse kinematics. The obtained results are compared with available direct kinematics and neutron irradiation measurements. (author)

  10. Determining the dissolution rates of actinide glasses: A time and temperature Product Consistency Test study

    Vitrification has been identified as one potential option for the e materials such as Americium (Am), Curium (Cm), Neptunium (Np), and Plutonium (Pu). A process is being developed at the Savannah River Site to safely vitrify all of the highly radioactive Am/Cm material and a portion of the fissile (Pu) actinide materials stored on site. Vitrification of the Am/Cm will allow the material to be transported and easily stored at the Oak Ridge National Laboratory. The Am/Cm glass has been specifically designed to be (1) highly durable in aqueous environments and (2) selectively attacked by nitric acid to allow recovery of the valuable Am and Cm isotopes. A similar glass composition will allow for safe storage of surplus plutonium. This paper will address the composition, relative durability, and dissolution rate characteristics of the actinide glass, Loeffler Target, that will be used in the Americium/Curium Vitrification Project at Westinghouse Savannah River Company near Aiken, South Carolina. The first part discusses the tests performed on the Loeffler Target Glass concerning instantaneous dissolution rates. The second part presents information concerning pseudo-activation energy for the one week glass dissolution process

  11. Studies of actinides in a superanoxic fjord

    Water column and sediment profiles of Pu, Am, Th and U have been obtained in the superanoxic Framvaren fjord, southern Norway. The concentration of bomb test fallout Pu, Am as well as 'dissolved' Th in the bottom water are the highest recorded in the marine environment. The behaviour of the actinides in the anoxic water mass is to a large extent governed by the behaviour of the colloidal material. Ultrafiltration reveals that 40-60% of the actinides are associated to the large colloids, surprisingly this is valid also for U. The sediment acts as a source for Pu, Am, and Th to the water column but primarily as a sink for U. The remobilization of Pu, Am and Th is evident from the water column profiles which have similar diffusion shape profiles as other constituents originating from the sediments. The vertical eddy diffusion coefficient calculated from the Pu profile is in the same order of magnitude as reported from the H2S profile. Decreased bottom water concentrations (but a constant water column inventory) between 1989 and 1995 as well as pore water Pu concentrations nearly identical to the overlaying bottom water indicates that the present Pu flux from the sediments are low. Contrary to Pu and Am, the water column Th inventory (232Th and 230Th) continues to increase. The flux of 232Th from the sediments was determined from changes in water column inventory between 1989 and 1995 and from a pore water profile to be in the order of 2-8 Bq/m2/y. 208 refs

  12. Archetypes for actinide-specific chelating agents

    The complexes of uranium and thorium with monomeric hydroxamic acids can serve as archetypes for an optimized macrochelate designed for tetravalent actinides. The eight-coordinate complexes, Th(i-PrN(O)C(O)R)4, where R = tert-butyl or R = neopentyl, have been synthesized and their structures have been determined by x-ray diffraction. The bulky alkyl substituents impart remarkable volatility and hydrocarbon solubility to these complexes, and the steric interactions of these substituents largely determine the structures. When R = tert-butyl, the substituents occupy the corners of a tetrahedron and force the complex into a distorted cubic geometry with crystallographic S4 symmetry. Insertion of a methylene group between the carbonyl carbon and the tert-butyl group relaxes the steric requirements, and the coordination polyhedron of the neopentyl derivative is close to the mmmm isomer of the trigonal-faced dodecahedron. Uranium tetrachloride was quantitatively oxidized via an oxygen transfer reaction with two equivalents of N-phenylbenzohydroxamic acid anion (PBHA) in tetrahydrofuran (THF) to form UO2 Cl(PBHA)(THF)2 and benzanilide. The structure of the uranyl complex has been determined from x-ray diffraction data; the linear uranyl ion is surrounded by a planar pentagonal array composed of two hydroxamate oxygen atoms, a chloride ion and two THF oxygens, such that the chloride ion is opposite the hydroxamate group. That the THF and phenyl rings are twisted from this equatorial plane limits the molecular geometry to that of the C1 point group. Some aspects of the chemistry of hydroxamic acids and of their incorporation into molecules that may serve as precursors of tetravalent actinide specific sequestering agents have also been investigated

  13. Pyrometallurgical processes for recovery of actinide elements

    Battles, J.E.; Laidler, J.J.; McPheeters, C.C.; Miller, W.E.

    1994-01-01

    A metallic fuel alloy, nominally U-20-Pu-lOZr, is the key element of the Integral Fast Reactor (IFR) fuel cycle. Metallic fuel permits the use of an innovative, simple pyrometallurgical process, known as pyroprocessing, (the subject of this report), which features fused salt electrorefining of the spent fuel. Electrorefining separates the actinide elements from fission products, without producing a separate stream of plutonium. The plutonium-bearing product is contaminated with higher actinides and with a minor amount of rare earth fission products, making it diversion resistant while still suitable as a fuel material in the fast spectrum of the IFR core. The engineering-scale demonstration of this process will be conducted in the refurbished EBR-II Fuel Cycle Facility, which has entered the start-up phase. An additional pyrometallurgical process is under development for extracting transuranic (TRU) elements from Light Water Reactor (LWR) spent fuel in a form suitable for use as a feed to the IFR fuel cycle. Four candidate extraction processes have been investigated and shown to be chemically feasible. The main steps in each process are oxide reduction with calcium or lithium, regeneration of the reductant and recycle of the salt, and separation of the TRU product from the bulk uranium. Two processes, referred to as the lithium and salt transport (calcium reductant) processes, have been selected for engineering-scale demonstration, which is expected to start in late 1993. An integral part of pyroprocessing development is the treatment and packaging of high-level waste materials arising from the operations, along with the qualification of these waste forms for disposal in a geologic repository.

  14. Studies of actinides in a superanoxic fjord

    Roos, P.

    1997-04-01

    Water column and sediment profiles of Pu, Am, Th and U have been obtained in the superanoxic Framvaren fjord, southern Norway. The concentration of bomb test fallout Pu, Am as well as `dissolved` Th in the bottom water are the highest recorded in the marine environment. The behaviour of the actinides in the anoxic water mass is to a large extent governed by the behaviour of the colloidal material. Ultrafiltration reveals that 40-60% of the actinides are associated to the large colloids, surprisingly this is valid also for U. The sediment acts as a source for Pu, Am, and Th to the water column but primarily as a sink for U. The remobilization of Pu, Am and Th is evident from the water column profiles which have similar diffusion shape profiles as other constituents originating from the sediments. The vertical eddy diffusion coefficient calculated from the Pu profile is in the same order of magnitude as reported from the H{sub 2}S profile. Decreased bottom water concentrations (but a constant water column inventory) between 1989 and 1995 as well as pore water Pu concentrations nearly identical to the overlaying bottom water indicates that the present Pu flux from the sediments are low. Contrary to Pu and Am, the water column Th inventory ({sup 232}Th and {sup 230}Th) continues to increase. The flux of {sup 232}Th from the sediments was determined from changes in water column inventory between 1989 and 1995 and from a pore water profile to be in the order of 2-8 Bq/m{sup 2}/y. 208 refs.

  15. Pyrometallurgical processes for recovery of actinide elements

    A metallic fuel alloy, nominally U-20-Pu-lOZr, is the key element of the Integral Fast Reactor (IFR) fuel cycle. Metallic fuel permits the use of an innovative, simple pyrometallurgical process, known as pyroprocessing, (the subject of this report), which features fused salt electrorefining of the spent fuel. Electrorefining separates the actinide elements from fission products, without producing a separate stream of plutonium. The plutonium-bearing product is contaminated with higher actinides and with a minor amount of rare earth fission products, making it diversion resistant while still suitable as a fuel material in the fast spectrum of the IFR core. The engineering-scale demonstration of this process will be conducted in the refurbished EBR-II Fuel Cycle Facility, which has entered the start-up phase. An additional pyrometallurgical process is under development for extracting transuranic (TRU) elements from Light Water Reactor (LWR) spent fuel in a form suitable for use as a feed to the IFR fuel cycle. Four candidate extraction processes have been investigated and shown to be chemically feasible. The main steps in each process are oxide reduction with calcium or lithium, regeneration of the reductant and recycle of the salt, and separation of the TRU product from the bulk uranium. Two processes, referred to as the lithium and salt transport (calcium reductant) processes, have been selected for engineering-scale demonstration, which is expected to start in late 1993. An integral part of pyroprocessing development is the treatment and packaging of high-level waste materials arising from the operations, along with the qualification of these waste forms for disposal in a geologic repository

  16. Mechanical environmental transport of actinides and ¹³⁷Cs from an arid radioactive waste disposal site.

    Snow, Mathew S; Clark, Sue B; Morrison, Samuel S; Watrous, Matthew G; Olson, John E; Snyder, Darin C

    2015-10-01

    Aeolian and pluvial processes represent important mechanisms for the movement of actinides and fission products at the Earth's surface. Soil samples taken in the early 1970's near a Department of Energy radioactive waste disposal site (the Subsurface Disposal Area, SDA, located in southeastern Idaho) provide a case study for studying the mechanisms and characteristics of environmental actinide and (137)Cs transport in an arid environment. Multi-component mixing models suggest actinide contamination within 2.5 km of the SDA can be described by mixing between 2 distinct SDA end members and regional nuclear weapons fallout. The absence of chemical fractionation between (241)Am and (239+240)Pu with depth for samples beyond the northeastern corner and lack of (241)Am in-growth over time (due to (241)Pu decay) suggest mechanical transport and mixing of discrete contaminated particles under arid conditions. Occasional samples northeast of the SDA (the direction of the prevailing winds) contain anomalously high concentrations of Pu with (240)Pu/(239)Pu isotopic ratios statistically identical to those in the northeastern corner. Taken together, these data suggest flooding resulted in mechanical transport of contaminated particles into the area between the SDA and a flood containment dike in the northeastern corner, following which subsequent contamination spreading in the northeastern direction resulted from wind transport of discrete particles. PMID:26107287

  17. Long- Term Stability Study of Isotope Ratio Measurements Uranium and Thorium by Quadrupole Icp Mass Spectrometry

    Precise isotope ratio measurements of long-lived actinides at trace concentration levels are requite for the characterization of environmental samples (e.g. evidence and extent of 236U contaminate from radioactive waste; geological samples for dating, using the U-Pb method), and radioactive waste material

  18. Isotope and Nuclear Chemistry Division annual report, FY 1990, October 1, 1989--September 30, 1990

    This report describes some of the major research and development programs of the Isotope and Nuclear Chemistry Division during FY 1990. The report includes articles on weapons chemistry, environmental chemistry, actinide and transition metal chemistry, geochemistry, nuclear structure and reactions, biochemistry and nuclear medicine, materials chemistry, and INC Division facilities and laboratories

  19. Isotope ratios of uranium using high resolution inductively coupled plasma-mass spectrometry (ICP-MS)

    Actinide element isotope ratios have been determined in environmental samples using high resolution ICP-MS with ultrasonic nebulization. Precisions as low as 0.1% RSD have been achieved using various methods of acquisition. The methodology has been used for environmental monitoring of uranium isotope ratios as an indicator of nuclear activity. Also, it has been applied to calcite dating studies as a measure of past geochemical disturbances

  20. Sedimentary organic matter in two Spitsbergen fjords: Terrestrial and marine contributions based on carbon and nitrogen contents and stable isotopes composition

    Koziorowska, Katarzyna; Kuliński, Karol; Pempkowiak, Janusz

    2016-02-01

    The aim of this study was to estimate the spatial variability of organic carbon (Corg) and total nitrogen (Ntot) concentrations, Corg/Ntot ratios, stable isotopes of carbon and nitrogen (δ13Corg, δ15Ntot) and the proportions of autochthonous and allochtonous organic matter within recently deposited sediments of two Spitsbergen fjords: the Hornsund and the Adventfjord, which are affected to a different degree by the West Spitsbergen Current. Corg concentrations ranged from 1.38% to 1.98% in the Hornsund and from 1.73% to 3.85% in the Adventfjord. In both fjords the highest Corg concentrations were measured at the innermost stations and they decreased towards the mouths of the fjords. This suggests fresh water runoff to be an important source of organic matter (OM) for surface sediments. The results showed that both fjords differ significantly in terms of sedimentary organic matter characteristics. The samples from the Hornsund, except those from the innermost station in the Brepollen, had relatively low Corg/Ntot ratios, all within a narrow range (from 9.7 to 11.3). On the other hand significantly higher Corg/Ntot ratios, varying within a broad range (from 14.6 to 33.0), were measured in the Adventfjord. The samples from the Hornsund were characterized by higher δ13Corg (from -24.90‰ to -23.87‰) and δ15Ntot (from 3.02‰ to 4.93‰) than those from the Adventfjord (-25.94‰ to -24.69‰ and from 0.71‰ to 4.00‰, respectively). This is attributed to a larger proportion of marine organic matter. Using the two end-member approach proportions of terrestrial organic matter were evaluated. Terrestrial OM contribution for the Adventfjord was in the range of 82-83%, while in case of the Hornsund the results were in the range of 69-75%, with the exception of the innermost part of the fjord, where terrestrial organic matter contribution ranged from 80 to 82%. The strong positive correlation between δ13Corg and δ15Ntot was revealed. This was taken as an indicator

  1. Methods of high-sensitive analysis of actinides in liquid radioactive waste

    A complex of methods has been developed to determine actinides in liquid radioactive wastes for solving the problems of radiation, nuclear and ecological safety of nuclear reactors. The main method is based on the radiochemical separation of U, Np-Pu, Am-Cm on ion-exchange and extraction columns. An identification of radionuclides and determination of their content are performed using alpha-spectrometry. The microconcentrations of the sum of the main fissile materials U-235 and Pu-239 are determined with the usage of plastic track detectors. An independent method of U-238 content determination is the neutron activation analysis. Am-241 content is possible to determine with gamma-spectrometry. (author)

  2. Element Partitioning in Glass-Ceramic Designed for Actinides Immobilization

    2008-01-01

    <正>Glass-ceramics were designed for immobilization of actinides. In order to immobilizing more wastes in the matrix and to develop the optimum formulation for the glass-ceramic, it is necessary to study the

  3. An atomic beam source for actinide elements: concept and realization

    For ultratrace analysis of actinide elements and studies of their atomic properties with resonance ionization mass spectroscopy (RIMS), efficient and stable sources of actinide atomic beams are required. The thermodynamics and kinetics of the evaporation of actinide elements and oxides from a variety of metals were considered, including diffusion, desorption, and associative desorption. On this basis various sandwich-type filaments were studied. The most promising system was found to consist of tantalum as the backing material, an electrolytically deposited actinide hydroxide as the source of the element, and a titanium covering layer for its reduction to the metal. Such sandwich sources were experimentally proven to be well suited for the production of atomic beams of plutonium, curium, berkelium and californium at relatively low operating temperatures and with high and reproducible yields. (orig.)

  4. Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

    The abstract book of the International workshop on advanced techniques for actinide spectroscopy (ATAS 2012) include contributions concerning the following issues: environmental applications, NMR spectroscopy, vibrational spectroscopy, X-ray spectroscopy and theory, technical application: separation processes, emission spectroscopy.

  5. Solvent extraction process for partitioning actinides from HLLW

    A description and review of the solvent extraction process for partitioning actinides from HLLW is presented. TRUEX process, DIDPA process, DIAMEX process, TRPO process as well as related An (III)/Ln(III) separation process are briefly discussed

  6. Actinide targets for the synthesis of super-heavy elements

    Roberto, J. B.; Alexander, C. W.; Boll, R. A.; Burns, J. D.; Ezold, J. G.; Felker, L. K.; Hogle, S. L.; Rykaczewski, K. P.

    2015-12-01

    Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of 48Ca beams on actinide targets. These target materials, including 242Pu, 244Pu, 243Am, 245Cm, 248Cm, 249Cf, and 249Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including 249Bk, 251Cf, and 254Es are described.

  7. Distribution of actinide elements in sediments: leaching studies

    Previous investigations have shown that Fe and Mn oxides and organic matter can significantly influence the behavior of Pu and other actinides in the environment. A sequential leaching procedure has been developed in order to investigate the solid phase distribution of the actinides in riverine and marine sediments. Seven different sedimentary fractions are defined by this leaching experiment: an exchangeable metals fraction, an organic fraction, a carbonate fraction, a Mn oxide fraction, an amorphous Fe fraction, a crystalline Fe oxide fraction and a lattice-held or residual fraction. There is also the option of including a metal sufide fraction. A preliminary experiment, analyzing only the metals and not the actinide elements, indicates that this leaching procedure (with some modifications) is a viable procedure. The subsequent data should result in information concerning the geochemical history and behavior of these actinide elements in the environment

  8. Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

    Foerstendorf, Harald; Mueller, Katharina; Steudtner, Robin (eds.)

    2012-07-01

    The abstract book of the International workshop on advanced techniques for actinide spectroscopy (ATAS 2012) include contributions concerning the following issues: environmental applications, NMR spectroscopy, vibrational spectroscopy, X-ray spectroscopy and theory, technical application: separation processes, emission spectroscopy.

  9. Use of fast-spectrum reactors for actinide burning

    Finally, Integral Fast Reactor (IFR) pyroprocessing has been developed only in recent years and it appears to have potential as a relatively uncomplicated, effective actinide recovery process. In fact, actinide recycling occurs naturally in the IFR fuel cycle. Although still very much developmental, the entire IFR fuel cycle will be demonstrated on prototype-scale in conjunction with the EBR-II and its refurbished Fuel Cycle Facility starting in late 1991. A logical extension to this work, therefore, is to establish whether this IFR pyrochemical processing can be applied to extracting actinides from LWR spent fuel. This paper summarizes current thinking on the rationale for actinide recycle, its ramifications on the geologic repository and the current high-level waste management plans, and the necessary development programs. 4 figs., 4 tabs

  10. In-situ mineralization of actinides with phytic acid

    A new approach to the remediation of actinide contamination is described. A hydrolytically unstable organophosphorus compound, phytic acid, is introduced into the contaminated environment. In the short term (up to several hundred years), phytate acts as a cation exchanger to absorb mobile actinide ions from ground waters. Ultimately, phytate decomposes to release phosphate and promote the formation of insoluble phosphate mineral phases, considered an ideal medium to immobilize actinides, as it forms compounds with the lowest solubility of any candidate mineral species. This overview will discuss the rate of hydrolysis of phytic acid, the formation of lanthanide/actinide phosphate mineral forms, the cation exchange behavior of insoluble phytate, and results from laboratory demonstration of the application to soils from the Fernald site

  11. Natural Isotopes 238U I40k Content In Rigosol From The Area Of School Estate Good „Radmilovac” Of Faculty Of Agriculture, Zemun

    Distribution of natural gamma-emitting radionuclides 238U and 40K were determined in the soil profiles from the peach-trees field on experimental farm Radmilovac, southeast Belgrade. Internal soil morphology has been changed in 1992 when soil rigosol type with deep Ap-horizon (0-80 cm) has been formed by special treatment of parent soil, chernozem type. Gamma-spectrometry method is applied in measurement of radionuclide activities in soil samples by using hyperpure coaxial gamma-ray detector, Canberra type. Investigation results has been shown that the natural activity contents obtained in the experiment are within the range of normal backround activity according to UNSCEAR (2000) and that radionuclide activity decreased in the plant root zone

  12. Measurement of fission cross-section of actinides at n_TOF for advanced nuclear reactors

    Calviani, Marco; Montagnoli, G; Mastinu, P

    2009-01-01

    The subject of this thesis is the determination of high accuracy neutron-induced fission cross-sections of various isotopes - all of which radioactive - of interest for emerging nuclear technologies. The measurements had been performed at the CERN neutron time-of-flight facility n TOF. In particular, in this work, fission cross-sections on 233U, the main fissile isotope of the Th/U fuel cycle, and on the minor actinides 241Am, 243Am and 245Cm have been analyzed. Data on these isotopes are requested for the feasibility study of innovative nuclear systems (ADS and Generation IV reactors) currently being considered for energy production and radioactive waste transmutation. The measurements have been performed with a high performance Fast Ionization Chamber (FIC), in conjunction with an innovative data acquisition system based on Flash-ADCs. The first step in the analysis has been the reconstruction of the digitized signals, in order to extract the information required for the discrimination between fission fragm...

  13. Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

    Ramos, D.; Rodríguez-Tajes, C.; Caamaño, M.; Farget, F.; Audouin, L.; Benlliure, J.; Casarejos, E.; Clement, E.; Cortina, D.; Delaune, O.; Derkx, X.; Dijon, A.; Doré, D.; Fernández-Domínguez, B.; de France, G.; Heinz, A.; Jacquot, B.; Navin, A.; Paradela, C.; Rejmund, M.; Roger, T.; Salsac, M. D.; Schmitt, C.

    2016-03-01

    Experimental access to full isotopic fragment distributions is very important to determine the features of the fission process. However, the isotopic identification of fission fragments has been, in the past, partial and scarce. A solution based on the use of inverse kinematics to study transfer-induced fission of exotic actinides was carried out at GANIL, resulting in the first experiment accessing the full identification of a collection of fissioning systems and their corresponding fission fragment distribution. In these experiments, a 238U beam at 6.14 AMeV impinged on a carbon target to produce fissioning systems from U to Am by transfer reactions, and Cf by fusion reactions. Isotopic fission yields of 250Cf, 244Cm, 240Pu, 239Np and 238U are presented in this work. With this information, the average number of neutrons as a function of the atomic number of the fragments is calculated, which reflects the impact of nuclear structure around Z=50, N=80 on the production of fission fragments. The characteristics of the Super Long, Standard I, Standard II, and Standard III fission channels were extracted from fits of the fragment yields for different ranges of excitation energy. The position and contribution of the fission channels as function of excitation energy are presented.

  14. Radioactive Ion Beam Production by Fast-Neutron-Induced Fission in Actinide Targets at EURISOL

    Herrera-Martínez, Adonai

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, the production of high-intensity RIBs of specific neutron-rich isotopes is obtained by inducing fission in large-mass actinide targets. In our contribution, the use of uranium targets is shown to be advantageous to other materials, such as thorium. Therefore, in order to produce fissions in U-238 and reduce the plutonium inventory, a fast neutron energy spectrum is necessary. The large beam power required to achieve these RIB levels requires the use of a liquid proton-to-neutron converter. This article details the design parameters of the converter, with special attention to the coupled neutronics of the liquid converter and fission target. Calculations performed with the ...

  15. Organic / inorganic carbon content and isotope analysis of 3.1Ga Cleaverville Formation in Pilbara, Australia: Result of DXCL project

    Miki, T.; Kiyokawa, S.; Ito, T.; Yamaguchi, K. E.; Ikehara, M.

    2014-12-01

    DXCL project was targeted for 3.2-3.1 Ga hydrothermal chert-black shale (Dixon Island Formation) and black shale-banded iron formation (Cleaverville Formation). CL3 core (200m long) was drilled from 1) upper part of Black Shale Member (35m thick) to 2) lower part of BIF Member (165m thick) of the Cleaverville Formation. Here, the BIF Member can be divided into three submembers; Greenish shale-siderite (50m thick), Magnetite-siderite (55m thick) and Black shale-siderite (60m) submembers. In this study, we used bulk samples and samples treated by hot hydrochloric acid in order to extract organic carbon.  The Black shale Member consists of black carbonaceous matter and fine grain quartz (laminated greenish sideritic shale and white chert (lamination with inter-bedded greenish sideritic shale and siderite lamination. Hematite is identified near fractured part. The Black shale-siderite submember is composed of black shale, siderite and chert bands.  1) Siderite layers of these three submembers showedδ13Ccarb value of -14.6 to -3.8‰. Corg and δ13Corg content are 0.2% and -18.3 to -0.3‰. 2) Siderite grains within greenish sideritic shales showedδ13Ccarb value of -12.9 to +15.0‰. 3) Black shale of Corg and δ13Corg content in the BIF Member are 0.1% and -36.3 to -17.1‰ respectively.  We found great difference in values of δ13Ccarb of siderite. One is Corg-rich shale (up to +15.0‰) and the other is Corg-poor siderite layers (up to -3.8‰). The lighter value of siderite layers may be originated from precursor organic carbon which is strongly affected by biological activity.

  16. Ultrasensitive detection of actinides and technetium by laser resonance ionization mass spectrometry

    The application of laser resonance ionization mass spectrometry for the detection of extremely small numbers of atoms has been explored in the very recent years. High sensitivity and unambiguity in element and isotope identification can be achieved by three-step photoionization of the elements in the atomic state followed by time-of-flight mass analysis. The laser system for photoionization consists of three dye lasers which are pumped simultaneously by a copper vapor laser. For mass determination a time-of-flight spectrometer with a mass resolution better than 1500 is used. By ionization via autoionizing states and by saturation in each excitation step a detection limit of about 107 atoms of actinides or of technetium in the sample has been obtained

  17. New analytical methodology to reach the actinide determination accuracy ({+-} 2%) required by the OSMOSE program

    Boyer-Deslys, V.; Combaluzier, T.; Dalier, V.; Martin, J.C.; Viallesoubranne, C. [DRCP/SE2A/LAMM, CEA/VALRHO - Marcoule, BP 17171, 30207 Bagnols-sur-Ceze (France); Crozet, M. [LEHA, CEA/VALRHO - Marcoule, BP 17171, 30207 Bagnols-sur-Ceze (France)

    2008-07-01

    This article describes the analytical procedure optimized by LAMM (Laboratory for Analysis and Materials Methodology) in order to characterize the actinide-doped pellets used in the Osmose (Oscillation in Minerve of isotopes in eupraxis spectra) program (developed for transmutation reactor physics). Osmose aims at providing precise experimental data (absorption cross sections) for heavy nuclides (atomic mass from 232 to 245). This procedure requires the use of the analytical equipment and expertise of the LAMM: TIMS (Thermal Ionization Mass Spectrometer), ICP (Inductively Coupled Plasma) QMS (Quadrupole Mass Spectrometer), SFMS (Sector Field Mass Spectrometer), AES (Atomic Emission Spectrometer), alpha spectrometry and photo-gravimetric analysis. These techniques have met all the specification requirements: extended uncertainties (k=2) below {+-} 2% on the uranium and dopant concentrations, the impurity concentration and the americium-241 concentration.

  18. Novel drug delivery systems for actinides (uranium and plutonium) decontamination agents.

    Fattal, Elias; Tsapis, Nicolas; Phan, Guillaume

    2015-08-01

    The possibility of accidents in the nuclear industry or of nuclear terrorist attacks makes the development of new decontamination strategies crucial. Among radionuclides, actinides such as uranium and plutonium and their different isotopes are considered as the most dangerous contaminants, plutonium displaying mostly a radiological toxicity whereas uranium exhibits mainly a chemical toxicity. Contamination occurs through ingestion, skin or lung exposure with subsequent absorption and distribution of the radionuclides to different tissues where they induce damaging effects. Different chelating agents have been synthesized but their efficacy is limited by their low tissue specificity and high toxicity. For these reasons, several groups have developed smart delivery systems to increase the local concentration of the chelating agent or to improve its biodistribution. The aim of this review is to highlight these strategies. PMID:26144994

  19. Rare Earth element (REE) incorporation in natural calcite. Upper limits for actinide uptake in a secondary phase

    Stipp, S.L.S.; Christensen, J.T.; Waight, T.E. [Geological Inst., Univ. of Copenhagen (Denmark); Lakshtanov, L.Z. [Geological Inst., Univ. of Copenhagen (Denmark); Inst. of Experimental Mineralogy, Russian Academy of Science, Chernogolovka (Russian Federation); Baker, J.A. [School of Earth Sciences, Victoria Univ. of Wellington (New Zealand)

    2006-07-01

    Secondary minerals have the potential to sequester escaped actinides in the event of a radioactive waste repository failure, but currently, data to define their maximum uptake capacity are generally lacking. To estimate a maximum limit for solid solution in calcite, we took advantage of the behavioural similarities of the 4f-orbital lanthanides with some of the 5f-orbital actinides and used rare Earth element (REE) concentration as an analogue. A suite of 65 calcite samples, mostly pure single crystals, was assembled from a range of geological settings, ages and locations and analysed by isotope dilution MC-ICP-MS (multiple-collector inductively-coupled plasma mass spectroscopy). All samples were shown to contain significant lanthanide concentrations. The highest were in calcite formed from hydrothermal solutions and from carbonatite magma. Maximum total mole fraction of REE was 4.72 x 10{sup -4}, which represents one substituted atom for about 2000 Ca sites. In comparison, synthetic calcite, precipitated at growth rates slow enough to insure solid solution formation, incorporated 7.5 x 10{sup -4} mole fraction Eu(III). For performance assessment, we propose that 7.5 mmole substitution/kg calcite should be considered the upper limit for actinide incorporation in secondary calcite. The largest source of uncertainty in this estimate results from extrapolating lanthanide data to actinides. However, the data offer confidence that for waters in the hydrothermal temperature range, such as in the near-field, or at groundwater temperatures, such as in the far-field, if calcite formation is favoured and actinides are present, those with behaviour like the trivalent lanthanides, especially Am{sup 3+} and Cm{sup 3+}, will be incorporated. REE are abundant and widely distributed, and they have remained in calcite for millions of years. Thus, one can be certain that incorporated actinides will also remain immobilised in calcite formed in fractures and pore spaces, as long as

  20. The OSMOSE program for the qualification of integral cross sections of actinides: Preliminary results in a PWR-UOx spectrum

    The need for improved nuclear data for minor actinides has been stressed by various organizations throughout the world - especially for studies relating to plutonium management, waste incineration, transmutation of waste, and Pu burning in future nuclear concepts. Several international programs have indicated a strong desire to obtain accurate integral reaction rate data for improving the major and minor actinides cross sections. Data on major actinides (i.e. 235U, 236U, 238U, 239Pu, 240Pu, 241Pu, 242Pu and 241Am) are reasonably well-known and available in the Evaluated Nuclear Data Files (JEFF, JENDL, ENDF-BX However information on the minor actinides (i.e. 232Th, 233U, 237Np, 238Pu, 242Am, 243Am, 243Cm, 235Cm, 244Cm, 245Cm, 246Cm and 247Cm) is less well-known and considered to be relatively poor in some cases, having to rely on model and extrapolation of few data points. In this framework, the ambitious OSMOSE program between the Commissariat a l'Energie Atomique (CEA), Electricite de France (EDF) and the U.S. Dept. of Energy (DOE) has been undertaken with the aim of measuring the integral absorption rate parameters of actinides in the MINERVE experimental facility located at the CEA Cadarache Research Center. The OSMOSE Program (Oscillation in Minerve of isotopes in 'Eupraxic' Spectra) includes a complete analytical program associated with the experimental measurement program and aims at understanding and resolving potential discrepancies between calculated and measured values. In the OSMOSE program, the reactivity worth of samples containing separated actinides are measured in different neutron spectra using an oscillation technique with an overall expected accuracy better than 3%. Reactivity effects of less than 10 pcm (0.0001 or approximately 1.5 cents) are measured and compared with calibrations to determine the differential reactivity-worth of the individual samples. The first experimental results were obtained with a very good reproducibility in 2005 and